re PR fortran/37802 (Improve wording for matmul bound checking)

2018-09-16  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/37802
	* frontend-passes.c (B_ERROR): New macro for matmul bounds
	checking error messages.
	(C_ERROR): Likewise.
	(inline_matmul_assign): Reorganize bounds checking, use B_ERROR
	and C_ERROR macros.

2018-09-16  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/37802
	* gfortran.dg/matmul_bounds_13.f90: New test case.
	* gfortran.dg/inline_matmul_15.f90:  Adjust test for runtime
	error.
	* gfortran.dg/matmul_5.f90: Likewise.
	* gfortran.dg/matmul_bounds_10.f90: Likewise.
	* gfortran.dg/matmul_bounds_11.f90: Likewise.
	* gfortran.dg/matmul_bounds_2.f90: Likewise.
	* gfortran.dg/matmul_bounds_4.f90: Likewise.
	* gfortran.dg/matmul_bounds_5.f90: Likewise.

2018-09-16  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/37802
	* m4/matmul_internal.m4: Adjust error messages.
        * generated/matmul_c10.c: Regenerated.
        * generated/matmul_c16.c: Regenerated.
        * generated/matmul_c4.c: Regenerated.
        * generated/matmul_c8.c: Regenerated.
        * generated/matmul_i1.c: Regenerated.
        * generated/matmul_i16.c: Regenerated.
        * generated/matmul_i2.c: Regenerated.
        * generated/matmul_i4.c: Regenerated.
        * generated/matmul_i8.c: Regenerated.
        * generated/matmul_r10.c: Regenerated.
        * generated/matmul_r16.c: Regenerated.
        * generated/matmul_r4.c: Regenerated.
        * generated/matmul_r8.c: Regenerated.
        * generated/matmulavx128_c10.c: Regenerated.
        * generated/matmulavx128_c16.c: Regenerated.
        * generated/matmulavx128_c4.c: Regenerated.
        * generated/matmulavx128_c8.c: Regenerated.
        * generated/matmulavx128_i1.c: Regenerated.
        * generated/matmulavx128_i16.c: Regenerated.
        * generated/matmulavx128_i2.c: Regenerated.
        * generated/matmulavx128_i4.c: Regenerated.
        * generated/matmulavx128_i8.c: Regenerated.
        * generated/matmulavx128_r10.c: Regenerated.
        * generated/matmulavx128_r16.c: Regenerated.
        * generated/matmulavx128_r4.c: Regenerated.
        * generated/matmulavx128_r8.c: Regenerated.

From-SVN: r264349

26 files changed, 2093 insertions, 1092 deletions

diff --git a/libgfortran/generated/matmul_c10.c b/libgfortran/generated/matmul_c10.c
index 462d71e..ac42158 100644
--- a/libgfortran/generated/matmul_c10.c
+++ b/libgfortran/generated/matmul_c10.c
@@ -144,8 +144,8 @@ matmul_c10_avx (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_c10_avx (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_c10_avx (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_c10_avx (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_c10_avx (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_c10_avx2 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_c10_avx2 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_c10_avx2 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_c10_avx2 (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_c10_avx2 (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_c10_avx512f (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_c10_avx512f (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_c10_avx512f (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_c10_avx512f (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_c10_avx512f (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_c10_vanilla (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_c10_vanilla (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_c10_vanilla (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_c10_vanilla (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_c10_vanilla (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_c10 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_c10 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_c10 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_c10 (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_c10 (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_c16.c b/libgfortran/generated/matmul_c16.c
index 2062739..ad2246c 100644
--- a/libgfortran/generated/matmul_c16.c
+++ b/libgfortran/generated/matmul_c16.c
@@ -144,8 +144,8 @@ matmul_c16_avx (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_c16_avx (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_c16_avx (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_c16_avx (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_c16_avx (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_c16_avx2 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_c16_avx2 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_c16_avx2 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_c16_avx2 (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_c16_avx2 (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_c16_avx512f (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_c16_avx512f (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_c16_avx512f (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_c16_avx512f (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_c16_avx512f (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_c16_vanilla (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_c16_vanilla (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_c16_vanilla (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_c16_vanilla (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_c16_vanilla (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_c16 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_c16 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_c16 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_c16 (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_c16 (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_c4.c b/libgfortran/generated/matmul_c4.c
index 91d193d..7793fc1 100644
--- a/libgfortran/generated/matmul_c4.c
+++ b/libgfortran/generated/matmul_c4.c
@@ -144,8 +144,8 @@ matmul_c4_avx (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_c4_avx (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_c4_avx (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_c4_avx (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_c4_avx (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_c4_avx2 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_c4_avx2 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_c4_avx2 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_c4_avx2 (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_c4_avx2 (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_c4_avx512f (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_c4_avx512f (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_c4_avx512f (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_c4_avx512f (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_c4_avx512f (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_c4_vanilla (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_c4_vanilla (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_c4_vanilla (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_c4_vanilla (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_c4_vanilla (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_c4 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_c4 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_c4 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_c4 (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_c4 (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_c8.c b/libgfortran/generated/matmul_c8.c
index 425af85..8525dc8 100644
--- a/libgfortran/generated/matmul_c8.c
+++ b/libgfortran/generated/matmul_c8.c
@@ -144,8 +144,8 @@ matmul_c8_avx (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_c8_avx (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_c8_avx (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_c8_avx (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_c8_avx (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_c8_avx2 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_c8_avx2 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_c8_avx2 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_c8_avx2 (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_c8_avx2 (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_c8_avx512f (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_c8_avx512f (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_c8_avx512f (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_c8_avx512f (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_c8_avx512f (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_c8_vanilla (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_c8_vanilla (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_c8_vanilla (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_c8_vanilla (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_c8_vanilla (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_c8 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_c8 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_c8 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_c8 (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_c8 (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_i1.c b/libgfortran/generated/matmul_i1.c
index 0c9335d..bb5bddb 100644
--- a/libgfortran/generated/matmul_i1.c
+++ b/libgfortran/generated/matmul_i1.c
@@ -144,8 +144,8 @@ matmul_i1_avx (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_i1_avx (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_i1_avx (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_i1_avx (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_i1_avx (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_i1_avx2 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_i1_avx2 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_i1_avx2 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_i1_avx2 (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_i1_avx2 (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_i1_avx512f (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_i1_avx512f (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_i1_avx512f (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_i1_avx512f (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_i1_avx512f (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_i1_vanilla (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_i1_vanilla (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_i1_vanilla (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_i1_vanilla (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_i1_vanilla (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_i1 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_i1 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_i1 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_i1 (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_i1 (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_i16.c b/libgfortran/generated/matmul_i16.c
index b9334b3..4f36a5b 100644
--- a/libgfortran/generated/matmul_i16.c
+++ b/libgfortran/generated/matmul_i16.c
@@ -144,8 +144,8 @@ matmul_i16_avx (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_i16_avx (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_i16_avx (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_i16_avx (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_i16_avx (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_i16_avx2 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_i16_avx2 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_i16_avx2 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_i16_avx2 (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_i16_avx2 (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_i16_avx512f (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_i16_avx512f (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_i16_avx512f (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_i16_avx512f (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_i16_avx512f (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_i16_vanilla (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_i16_vanilla (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_i16_vanilla (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_i16_vanilla (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_i16_vanilla (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_i16 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_i16 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_i16 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_i16 (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_i16 (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_i2.c b/libgfortran/generated/matmul_i2.c
index e4246e9..2aea3b4 100644
--- a/libgfortran/generated/matmul_i2.c
+++ b/libgfortran/generated/matmul_i2.c
@@ -144,8 +144,8 @@ matmul_i2_avx (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_i2_avx (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_i2_avx (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_i2_avx (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_i2_avx (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_i2_avx2 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_i2_avx2 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_i2_avx2 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_i2_avx2 (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_i2_avx2 (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_i2_avx512f (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_i2_avx512f (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_i2_avx512f (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_i2_avx512f (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_i2_avx512f (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_i2_vanilla (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_i2_vanilla (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_i2_vanilla (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_i2_vanilla (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_i2_vanilla (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_i2 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_i2 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_i2 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_i2 (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_i2 (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_i4.c b/libgfortran/generated/matmul_i4.c
index 78cf27c..4ef9a0a 100644
--- a/libgfortran/generated/matmul_i4.c
+++ b/libgfortran/generated/matmul_i4.c
@@ -144,8 +144,8 @@ matmul_i4_avx (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_i4_avx (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_i4_avx (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_i4_avx (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_i4_avx (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_i4_avx2 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_i4_avx2 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_i4_avx2 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_i4_avx2 (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_i4_avx2 (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_i4_avx512f (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_i4_avx512f (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_i4_avx512f (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_i4_avx512f (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_i4_avx512f (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_i4_vanilla (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_i4_vanilla (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_i4_vanilla (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_i4_vanilla (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_i4_vanilla (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_i4 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_i4 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_i4 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_i4 (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_i4 (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_i8.c b/libgfortran/generated/matmul_i8.c
index cf8c401..e0c93ce 100644
--- a/libgfortran/generated/matmul_i8.c
+++ b/libgfortran/generated/matmul_i8.c
@@ -144,8 +144,8 @@ matmul_i8_avx (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_i8_avx (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_i8_avx (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_i8_avx (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_i8_avx (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_i8_avx2 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_i8_avx2 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_i8_avx2 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_i8_avx2 (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_i8_avx2 (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_i8_avx512f (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_i8_avx512f (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_i8_avx512f (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_i8_avx512f (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_i8_avx512f (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_i8_vanilla (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_i8_vanilla (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_i8_vanilla (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_i8_vanilla (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_i8_vanilla (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_i8 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_i8 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_i8 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_i8 (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_i8 (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_r10.c b/libgfortran/generated/matmul_r10.c
index e4309c8..5d90454 100644
--- a/libgfortran/generated/matmul_r10.c
+++ b/libgfortran/generated/matmul_r10.c
@@ -144,8 +144,8 @@ matmul_r10_avx (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_r10_avx (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_r10_avx (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_r10_avx (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_r10_avx (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_r10_avx2 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_r10_avx2 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_r10_avx2 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_r10_avx2 (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_r10_avx2 (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_r10_avx512f (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_r10_avx512f (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_r10_avx512f (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_r10_avx512f (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_r10_avx512f (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_r10_vanilla (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_r10_vanilla (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_r10_vanilla (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_r10_vanilla (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_r10_vanilla (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_r10 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_r10 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_r10 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_r10 (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_r10 (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_r16.c b/libgfortran/generated/matmul_r16.c
index 1ab5546..dab10b0 100644
--- a/libgfortran/generated/matmul_r16.c
+++ b/libgfortran/generated/matmul_r16.c
@@ -144,8 +144,8 @@ matmul_r16_avx (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_r16_avx (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_r16_avx (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_r16_avx (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_r16_avx (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_r16_avx2 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_r16_avx2 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_r16_avx2 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_r16_avx2 (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_r16_avx2 (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_r16_avx512f (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_r16_avx512f (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_r16_avx512f (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_r16_avx512f (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_r16_avx512f (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_r16_vanilla (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_r16_vanilla (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_r16_vanilla (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_r16_vanilla (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_r16_vanilla (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_r16 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_r16 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_r16 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_r16 (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_r16 (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_r4.c b/libgfortran/generated/matmul_r4.c
index 97dba98..c9c31df 100644
--- a/libgfortran/generated/matmul_r4.c
+++ b/libgfortran/generated/matmul_r4.c
@@ -144,8 +144,8 @@ matmul_r4_avx (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_r4_avx (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_r4_avx (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_r4_avx (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_r4_avx (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_r4_avx2 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_r4_avx2 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_r4_avx2 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_r4_avx2 (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_r4_avx2 (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_r4_avx512f (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_r4_avx512f (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_r4_avx512f (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_r4_avx512f (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_r4_avx512f (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_r4_vanilla (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_r4_vanilla (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_r4_vanilla (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_r4_vanilla (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_r4_vanilla (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_r4 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_r4 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_r4 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_r4 (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_r4 (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmul_r8.c b/libgfortran/generated/matmul_r8.c
index 5e4c950..4c5823f 100644
--- a/libgfortran/generated/matmul_r8.c
+++ b/libgfortran/generated/matmul_r8.c
@@ -144,8 +144,8 @@ matmul_r8_avx (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -153,8 +153,8 @@ matmul_r8_avx (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -162,17 +162,15 @@ matmul_r8_avx (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -213,7 +211,9 @@ matmul_r8_avx (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -258,7 +258,18 @@ matmul_r8_avx (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -701,8 +712,8 @@ matmul_r8_avx2 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -710,8 +721,8 @@ matmul_r8_avx2 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -719,17 +730,15 @@ matmul_r8_avx2 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -770,7 +779,9 @@ matmul_r8_avx2 (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -815,7 +826,18 @@ matmul_r8_avx2 (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1258,8 +1280,8 @@ matmul_r8_avx512f (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1267,8 +1289,8 @@ matmul_r8_avx512f (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1276,17 +1298,15 @@ matmul_r8_avx512f (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1327,7 +1347,9 @@ matmul_r8_avx512f (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1372,7 +1394,18 @@ matmul_r8_avx512f (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -1829,8 +1862,8 @@ matmul_r8_vanilla (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1838,8 +1871,8 @@ matmul_r8_vanilla (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -1847,17 +1880,15 @@ matmul_r8_vanilla (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -1898,7 +1929,9 @@ matmul_r8_vanilla (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -1943,7 +1976,18 @@ matmul_r8_vanilla (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -2460,8 +2504,8 @@ matmul_r8 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2469,8 +2513,8 @@ matmul_r8 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -2478,17 +2522,15 @@ matmul_r8 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -2529,7 +2571,9 @@ matmul_r8 (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -2574,7 +2618,18 @@ matmul_r8 (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_c10.c b/libgfortran/generated/matmulavx128_c10.c
index 5cb0f6a..0391471 100644
--- a/libgfortran/generated/matmulavx128_c10.c
+++ b/libgfortran/generated/matmulavx128_c10.c
@@ -109,8 +109,8 @@ matmul_c10_avx128_fma3 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_c10_avx128_fma3 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_c10_avx128_fma3 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_c10_avx128_fma3 (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_c10_avx128_fma3 (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_c10_avx128_fma4 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_c10_avx128_fma4 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_c10_avx128_fma4 (gfc_array_c10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_c10_avx128_fma4 (gfc_array_c10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_c10_avx128_fma4 (gfc_array_c10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_c16.c b/libgfortran/generated/matmulavx128_c16.c
index 66272fe..876fc69 100644
--- a/libgfortran/generated/matmulavx128_c16.c
+++ b/libgfortran/generated/matmulavx128_c16.c
@@ -109,8 +109,8 @@ matmul_c16_avx128_fma3 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_c16_avx128_fma3 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_c16_avx128_fma3 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_c16_avx128_fma3 (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_c16_avx128_fma3 (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_c16_avx128_fma4 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_c16_avx128_fma4 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_c16_avx128_fma4 (gfc_array_c16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_c16_avx128_fma4 (gfc_array_c16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_c16_avx128_fma4 (gfc_array_c16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_c4.c b/libgfortran/generated/matmulavx128_c4.c
index f6e06e2..a577887 100644
--- a/libgfortran/generated/matmulavx128_c4.c
+++ b/libgfortran/generated/matmulavx128_c4.c
@@ -109,8 +109,8 @@ matmul_c4_avx128_fma3 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_c4_avx128_fma3 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_c4_avx128_fma3 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_c4_avx128_fma3 (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_c4_avx128_fma3 (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_c4_avx128_fma4 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_c4_avx128_fma4 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_c4_avx128_fma4 (gfc_array_c4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_c4_avx128_fma4 (gfc_array_c4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_c4_avx128_fma4 (gfc_array_c4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_c8.c b/libgfortran/generated/matmulavx128_c8.c
index accc69c..2ca4701 100644
--- a/libgfortran/generated/matmulavx128_c8.c
+++ b/libgfortran/generated/matmulavx128_c8.c
@@ -109,8 +109,8 @@ matmul_c8_avx128_fma3 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_c8_avx128_fma3 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_c8_avx128_fma3 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_c8_avx128_fma3 (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_c8_avx128_fma3 (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_c8_avx128_fma4 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_c8_avx128_fma4 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_c8_avx128_fma4 (gfc_array_c8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_c8_avx128_fma4 (gfc_array_c8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_c8_avx128_fma4 (gfc_array_c8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_i1.c b/libgfortran/generated/matmulavx128_i1.c
index 48b15c8..1af28d1 100644
--- a/libgfortran/generated/matmulavx128_i1.c
+++ b/libgfortran/generated/matmulavx128_i1.c
@@ -109,8 +109,8 @@ matmul_i1_avx128_fma3 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_i1_avx128_fma3 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_i1_avx128_fma3 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_i1_avx128_fma3 (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_i1_avx128_fma3 (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_i1_avx128_fma4 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_i1_avx128_fma4 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_i1_avx128_fma4 (gfc_array_i1 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_i1_avx128_fma4 (gfc_array_i1 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_i1_avx128_fma4 (gfc_array_i1 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_i16.c b/libgfortran/generated/matmulavx128_i16.c
index 319321e..37a4125 100644
--- a/libgfortran/generated/matmulavx128_i16.c
+++ b/libgfortran/generated/matmulavx128_i16.c
@@ -109,8 +109,8 @@ matmul_i16_avx128_fma3 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_i16_avx128_fma3 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_i16_avx128_fma3 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_i16_avx128_fma3 (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_i16_avx128_fma3 (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_i16_avx128_fma4 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_i16_avx128_fma4 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_i16_avx128_fma4 (gfc_array_i16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_i16_avx128_fma4 (gfc_array_i16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_i16_avx128_fma4 (gfc_array_i16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_i2.c b/libgfortran/generated/matmulavx128_i2.c
index 4d8945b..033133a 100644
--- a/libgfortran/generated/matmulavx128_i2.c
+++ b/libgfortran/generated/matmulavx128_i2.c
@@ -109,8 +109,8 @@ matmul_i2_avx128_fma3 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_i2_avx128_fma3 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_i2_avx128_fma3 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_i2_avx128_fma3 (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_i2_avx128_fma3 (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_i2_avx128_fma4 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_i2_avx128_fma4 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_i2_avx128_fma4 (gfc_array_i2 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_i2_avx128_fma4 (gfc_array_i2 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_i2_avx128_fma4 (gfc_array_i2 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_i4.c b/libgfortran/generated/matmulavx128_i4.c
index acaa00a..7cc2ba8 100644
--- a/libgfortran/generated/matmulavx128_i4.c
+++ b/libgfortran/generated/matmulavx128_i4.c
@@ -109,8 +109,8 @@ matmul_i4_avx128_fma3 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_i4_avx128_fma3 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_i4_avx128_fma3 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_i4_avx128_fma3 (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_i4_avx128_fma3 (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_i4_avx128_fma4 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_i4_avx128_fma4 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_i4_avx128_fma4 (gfc_array_i4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_i4_avx128_fma4 (gfc_array_i4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_i4_avx128_fma4 (gfc_array_i4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_i8.c b/libgfortran/generated/matmulavx128_i8.c
index 56e8516..5628064 100644
--- a/libgfortran/generated/matmulavx128_i8.c
+++ b/libgfortran/generated/matmulavx128_i8.c
@@ -109,8 +109,8 @@ matmul_i8_avx128_fma3 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_i8_avx128_fma3 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_i8_avx128_fma3 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_i8_avx128_fma3 (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_i8_avx128_fma3 (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_i8_avx128_fma4 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_i8_avx128_fma4 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_i8_avx128_fma4 (gfc_array_i8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_i8_avx128_fma4 (gfc_array_i8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_i8_avx128_fma4 (gfc_array_i8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_r10.c b/libgfortran/generated/matmulavx128_r10.c
index 880c9d9..68c0ef3 100644
--- a/libgfortran/generated/matmulavx128_r10.c
+++ b/libgfortran/generated/matmulavx128_r10.c
@@ -109,8 +109,8 @@ matmul_r10_avx128_fma3 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_r10_avx128_fma3 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_r10_avx128_fma3 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_r10_avx128_fma3 (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_r10_avx128_fma3 (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_r10_avx128_fma4 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_r10_avx128_fma4 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_r10_avx128_fma4 (gfc_array_r10 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_r10_avx128_fma4 (gfc_array_r10 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_r10_avx128_fma4 (gfc_array_r10 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_r16.c b/libgfortran/generated/matmulavx128_r16.c
index 328e251..fadff1d 100644
--- a/libgfortran/generated/matmulavx128_r16.c
+++ b/libgfortran/generated/matmulavx128_r16.c
@@ -109,8 +109,8 @@ matmul_r16_avx128_fma3 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_r16_avx128_fma3 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_r16_avx128_fma3 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_r16_avx128_fma3 (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_r16_avx128_fma3 (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_r16_avx128_fma4 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_r16_avx128_fma4 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_r16_avx128_fma4 (gfc_array_r16 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_r16_avx128_fma4 (gfc_array_r16 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_r16_avx128_fma4 (gfc_array_r16 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_r4.c b/libgfortran/generated/matmulavx128_r4.c
index 013a180..accec42 100644
--- a/libgfortran/generated/matmulavx128_r4.c
+++ b/libgfortran/generated/matmulavx128_r4.c
@@ -109,8 +109,8 @@ matmul_r4_avx128_fma3 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_r4_avx128_fma3 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_r4_avx128_fma3 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_r4_avx128_fma3 (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_r4_avx128_fma3 (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_r4_avx128_fma4 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_r4_avx128_fma4 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_r4_avx128_fma4 (gfc_array_r4 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_r4_avx128_fma4 (gfc_array_r4 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_r4_avx128_fma4 (gfc_array_r4 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
diff --git a/libgfortran/generated/matmulavx128_r8.c b/libgfortran/generated/matmulavx128_r8.c
index 4da59f9..06e0437 100644
--- a/libgfortran/generated/matmulavx128_r8.c
+++ b/libgfortran/generated/matmulavx128_r8.c
@@ -109,8 +109,8 @@ matmul_r8_avx128_fma3 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -118,8 +118,8 @@ matmul_r8_avx128_fma3 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -127,17 +127,15 @@ matmul_r8_avx128_fma3 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -178,7 +176,9 @@ matmul_r8_avx128_fma3 (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -223,7 +223,18 @@ matmul_r8_avx128_fma3 (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;
@@ -667,8 +678,8 @@ matmul_r8_avx128_fma4 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -676,8 +687,8 @@ matmul_r8_avx128_fma4 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic: is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
       else
@@ -685,17 +696,15 @@ matmul_r8_avx128_fma4 (gfc_array_r8 * const restrict retarray,
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(a,0);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,0);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 1:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 1 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 
 	  arg_extent = GFC_DESCRIPTOR_EXTENT(b,1);
 	  ret_extent = GFC_DESCRIPTOR_EXTENT(retarray,1);
 	  if (arg_extent != ret_extent)
-	    runtime_error ("Incorrect extent in return array in"
-			   " MATMUL intrinsic for dimension 2:"
-			   " is %ld, should be %ld",
+	    runtime_error ("Array bound mismatch for dimension 2 of "
+	    		   "array (%ld/%ld) ",
 			   (long int) ret_extent, (long int) arg_extent);
 	}
     }
@@ -736,7 +745,9 @@ matmul_r8_avx128_fma4 (gfc_array_r8 * const restrict retarray,
   if (count != GFC_DESCRIPTOR_EXTENT(b,0))
     {
       if (count > 0 || GFC_DESCRIPTOR_EXTENT(b,0) > 0)
-	runtime_error ("dimension of array B incorrect in MATMUL intrinsic");
+	runtime_error ("Incorrect extent in argument B in MATMUL intrinsic "
+		       "in dimension 1: is %ld, should be %ld",
+		       (long int) GFC_DESCRIPTOR_EXTENT(b,0), (long int) count);
     }
 
   if (GFC_DESCRIPTOR_RANK (b) == 1)
@@ -781,7 +792,18 @@ matmul_r8_avx128_fma4 (gfc_array_r8 * const restrict retarray,
       if (lda > 0 && ldb > 0 && ldc > 0 && m > 1 && n > 1 && k > 1)
 	{
 	  assert (gemm != NULL);
-	  gemm (axstride == 1 ? "N" : "T", bxstride == 1 ? "N" : "T", &m,
+	  const char *transa, *transb;
+	  if (try_blas & 2)
+	    transa = "C";
+	  else
+	    transa = axstride == 1 ? "N" : "T";
+
+	  if (try_blas & 4)
+	    transb = "C";
+	  else
+	    transb = bxstride == 1 ? "N" : "T";
+
+	  gemm (transa, transb , &m,
 		&n, &k,	&one, abase, &lda, bbase, &ldb, &zero, dest,
 		&ldc, 1, 1);
 	  return;