s390: Recognize further vpdi and vmr{l,h} pattern

Deal with cases where vpdi and vmr{l,h} are still applicable if the
operands of those instructions are swapped.  For example, currently for

V2DI foo (V2DI x)
{
  return (V2DI) {x[1], x[0]};
}

the assembler sequence

vlgvg   %r1,%v24,1
vzero   %v0
vlvgg   %v0,%r1,0
vmrhg   %v24,%v0,%v24

is emitted.  With this patch a single vpdi is emitted.

Extensive tests are included in a subsequent patch of this series where
more cases are covered.

gcc/ChangeLog:

	* config/s390/s390.cc (expand_perm_with_merge): Deal with cases
	where vmr{l,h} are still applicable if the operands are swapped.
	(expand_perm_with_vpdi): Likewise for vpdi.

1 files changed, 90 insertions, 28 deletions

diff --git a/gcc/config/s390/s390.cc b/gcc/config/s390/s390.cc
index 64f56d8..185eb59 100644
--- a/gcc/config/s390/s390.cc
+++ b/gcc/config/s390/s390.cc
@@ -17532,40 +17532,86 @@ struct expand_vec_perm_d
 static bool
 expand_perm_with_merge (const struct expand_vec_perm_d &d)
 {
-  bool merge_lo_p = true;
-  bool merge_hi_p = true;
-
-  if (d.nelt % 2)
+  static const unsigned char hi_perm_di[2] = {0, 2};
+  static const unsigned char hi_perm_si[4] = {0, 4, 1, 5};
+  static const unsigned char hi_perm_hi[8] = {0, 8, 1, 9, 2, 10, 3, 11};
+  static const unsigned char hi_perm_qi[16]
+    = {0, 16, 1, 17, 2, 18, 3, 19, 4, 20, 5, 21, 6, 22, 7, 23};
+
+  static const unsigned char hi_perm_di_swap[2] = {2, 0};
+  static const unsigned char hi_perm_si_swap[4] = {4, 0, 6, 2};
+  static const unsigned char hi_perm_hi_swap[8] = {8, 0, 10, 2, 12, 4, 14, 6};
+  static const unsigned char hi_perm_qi_swap[16]
+    = {16, 0, 18, 2, 20, 4, 22, 6, 24, 8, 26, 10, 28, 12, 30, 14};
+
+  static const unsigned char lo_perm_di[2] = {1, 3};
+  static const unsigned char lo_perm_si[4] = {2, 6, 3, 7};
+  static const unsigned char lo_perm_hi[8] = {4, 12, 5, 13, 6, 14, 7, 15};
+  static const unsigned char lo_perm_qi[16]
+    = {8, 24, 9, 25, 10, 26, 11, 27, 12, 28, 13, 29, 14, 30, 15, 31};
+
+  static const unsigned char lo_perm_di_swap[2] = {3, 1};
+  static const unsigned char lo_perm_si_swap[4] = {5, 1, 7, 3};
+  static const unsigned char lo_perm_hi_swap[8] = {9, 1, 11, 3, 13, 5, 15, 7};
+  static const unsigned char lo_perm_qi_swap[16]
+    = {17, 1, 19, 3, 21, 5, 23, 7, 25, 9, 27, 11, 29, 13, 31, 15};
+
+  bool merge_lo_p = false;
+  bool merge_hi_p = false;
+  bool swap_operands_p = false;
+
+  if ((d.nelt == 2 && memcmp (d.perm, hi_perm_di, 2) == 0)
+      || (d.nelt == 4 && memcmp (d.perm, hi_perm_si, 4) == 0)
+      || (d.nelt == 8 && memcmp (d.perm, hi_perm_hi, 8) == 0)
+      || (d.nelt == 16 && memcmp (d.perm, hi_perm_qi, 16) == 0))
+    {
+      merge_hi_p = true;
+    }
+  else if ((d.nelt == 2 && memcmp (d.perm, hi_perm_di_swap, 2) == 0)
+	   || (d.nelt == 4 && memcmp (d.perm, hi_perm_si_swap, 4) == 0)
+	   || (d.nelt == 8 && memcmp (d.perm, hi_perm_hi_swap, 8) == 0)
+	   || (d.nelt == 16 && memcmp (d.perm, hi_perm_qi_swap, 16) == 0))
+    {
+      merge_hi_p = true;
+      swap_operands_p = true;
+    }
+  else if ((d.nelt == 2 && memcmp (d.perm, lo_perm_di, 2) == 0)
+	   || (d.nelt == 4 && memcmp (d.perm, lo_perm_si, 4) == 0)
+	   || (d.nelt == 8 && memcmp (d.perm, lo_perm_hi, 8) == 0)
+	   || (d.nelt == 16 && memcmp (d.perm, lo_perm_qi, 16) == 0))
+    {
+      merge_lo_p = true;
+    }
+  else if ((d.nelt == 2 && memcmp (d.perm, lo_perm_di_swap, 2) == 0)
+	   || (d.nelt == 4 && memcmp (d.perm, lo_perm_si_swap, 4) == 0)
+	   || (d.nelt == 8 && memcmp (d.perm, lo_perm_hi_swap, 8) == 0)
+	   || (d.nelt == 16 && memcmp (d.perm, lo_perm_qi_swap, 16) == 0))
+    {
+      merge_lo_p = true;
+      swap_operands_p = true;
+    }
+
+  if (!merge_lo_p && !merge_hi_p)
     return false;
 
-  // For V4SI this checks for: { 0, 4, 1, 5 }
-  for (int telt = 0; telt < d.nelt; telt++)
-    if (d.perm[telt] != telt / 2 + (telt % 2) * d.nelt)
-      {
-	merge_hi_p = false;
-	break;
-      }
+  if (d.testing_p)
+    return merge_lo_p || merge_hi_p;
 
-  if (!merge_hi_p)
+  rtx op0, op1;
+  if (swap_operands_p)
     {
-      // For V4SI this checks for: { 2, 6, 3, 7 }
-      for (int telt = 0; telt < d.nelt; telt++)
-	if (d.perm[telt] != (telt + d.nelt) / 2 + (telt % 2) * d.nelt)
-	  {
-	    merge_lo_p = false;
-	    break;
-	  }
+      op0 = d.op1;
+      op1 = d.op0;
     }
   else
-    merge_lo_p = false;
-
-  if (d.testing_p)
-    return merge_lo_p || merge_hi_p;
+    {
+      op0 = d.op0;
+      op1 = d.op1;
+    }
 
-  if (merge_lo_p || merge_hi_p)
-    s390_expand_merge (d.target, d.op0, d.op1, merge_hi_p);
+  s390_expand_merge (d.target, op0, op1, merge_hi_p);
 
-  return merge_lo_p || merge_hi_p;
+  return true;
 }
 
 /* Try to expand the vector permute operation described by D using the
@@ -17582,6 +17628,7 @@ expand_perm_with_vpdi (const struct expand_vec_perm_d &d)
 {
   bool vpdi1_p = false;
   bool vpdi4_p = false;
+  bool swap_operands_p = false;
   rtx op0_reg, op1_reg;
 
   // Only V2DI and V2DF are supported here.
@@ -17590,11 +17637,20 @@ expand_perm_with_vpdi (const struct expand_vec_perm_d &d)
 
   if (d.perm[0] == 0 && d.perm[1] == 3)
     vpdi1_p = true;
-
-  if ((d.perm[0] == 1 && d.perm[1] == 2)
+  else if (d.perm[0] == 2 && d.perm[1] == 1)
+    {
+      vpdi1_p = true;
+      swap_operands_p = true;
+    }
+  else if ((d.perm[0] == 1 && d.perm[1] == 2)
       || (d.perm[0] == 1 && d.perm[1] == 0)
       || (d.perm[0] == 3 && d.perm[1] == 2))
     vpdi4_p = true;
+  else if (d.perm[0] == 3 && d.perm[1] == 0)
+    {
+      vpdi4_p = true;
+      swap_operands_p = true;
+    }
 
   if (!vpdi1_p && !vpdi4_p)
     return false;
@@ -17611,6 +17667,12 @@ expand_perm_with_vpdi (const struct expand_vec_perm_d &d)
     op1_reg = op0_reg;
   else if (d.only_op1)
     op0_reg = op1_reg;
+  else if (swap_operands_p)
+    {
+      rtx tmp = op0_reg;
+      op0_reg = op1_reg;
+      op1_reg = tmp;
+    }
 
   if (vpdi1_p)
     emit_insn (gen_vpdi1 (d.vmode, d.target, op0_reg, op1_reg));