Fix inefficient vector constructor.

Changelog
gcc/
	PR target/92295
	* config/i386/i386-expand.c (ix86_expand_vector_init_concat)
	Enhance ix86_expand_vector_init_concat.

gcc/testsuite
	* gcc.target/i386/pr92295.c: New test.

From-SVN: r277946

4 files changed, 75 insertions, 78 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e723121..9a33aa1 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2019-11-08  Hongtao Liu  <Hongtao.liu@intel.com>
+
+	PR target/92295
+	* config/i386/i386-expand.c (ix86_expand_vector_init_concat)
+	Enhance ix86_expand_vector_init_concat.
+
 2019-11-08  Joseph Myers  <joseph@codesourcery.com>
 
 	* doc/invoke.texi (-Wold-style-definition): Document () not being
diff --git a/gcc/config/i386/i386-expand.c b/gcc/config/i386/i386-expand.c
index 6d3d14c..be040a1 100644
--- a/gcc/config/i386/i386-expand.c
+++ b/gcc/config/i386/i386-expand.c
@@ -13654,8 +13654,8 @@ static void
 ix86_expand_vector_init_concat (machine_mode mode,
 				rtx target, rtx *ops, int n)
 {
-  machine_mode cmode, hmode = VOIDmode, gmode = VOIDmode;
-  rtx first[16], second[8], third[4];
+  machine_mode half_mode = VOIDmode;
+  rtx half[2];
   rtvec v;
   int i, j;
 
@@ -13665,55 +13665,55 @@ ix86_expand_vector_init_concat (machine_mode mode,
       switch (mode)
 	{
 	case E_V16SImode:
-	  cmode = V8SImode;
+	  half_mode = V8SImode;
 	  break;
 	case E_V16SFmode:
-	  cmode = V8SFmode;
+	  half_mode = V8SFmode;
 	  break;
 	case E_V8DImode:
-	  cmode = V4DImode;
+	  half_mode = V4DImode;
 	  break;
 	case E_V8DFmode:
-	  cmode = V4DFmode;
+	  half_mode = V4DFmode;
 	  break;
 	case E_V8SImode:
-	  cmode = V4SImode;
+	  half_mode = V4SImode;
 	  break;
 	case E_V8SFmode:
-	  cmode = V4SFmode;
+	  half_mode = V4SFmode;
 	  break;
 	case E_V4DImode:
-	  cmode = V2DImode;
+	  half_mode = V2DImode;
 	  break;
 	case E_V4DFmode:
-	  cmode = V2DFmode;
+	  half_mode = V2DFmode;
 	  break;
 	case E_V4SImode:
-	  cmode = V2SImode;
+	  half_mode = V2SImode;
 	  break;
 	case E_V4SFmode:
-	  cmode = V2SFmode;
+	  half_mode = V2SFmode;
 	  break;
 	case E_V2DImode:
-	  cmode = DImode;
+	  half_mode = DImode;
 	  break;
 	case E_V2SImode:
-	  cmode = SImode;
+	  half_mode = SImode;
 	  break;
 	case E_V2DFmode:
-	  cmode = DFmode;
+	  half_mode = DFmode;
 	  break;
 	case E_V2SFmode:
-	  cmode = SFmode;
+	  half_mode = SFmode;
 	  break;
 	default:
 	  gcc_unreachable ();
 	}
 
-      if (!register_operand (ops[1], cmode))
-	ops[1] = force_reg (cmode, ops[1]);
-      if (!register_operand (ops[0], cmode))
-	ops[0] = force_reg (cmode, ops[0]);
+      if (!register_operand (ops[1], half_mode))
+	ops[1] = force_reg (half_mode, ops[1]);
+      if (!register_operand (ops[0], half_mode))
+	ops[0] = force_reg (half_mode, ops[0]);
       emit_insn (gen_rtx_SET (target, gen_rtx_VEC_CONCAT (mode, ops[0],
 							  ops[1])));
       break;
@@ -13722,16 +13722,16 @@ ix86_expand_vector_init_concat (machine_mode mode,
       switch (mode)
 	{
 	case E_V4DImode:
-	  cmode = V2DImode;
+	  half_mode = V2DImode;
 	  break;
 	case E_V4DFmode:
-	  cmode = V2DFmode;
+	  half_mode = V2DFmode;
 	  break;
 	case E_V4SImode:
-	  cmode = V2SImode;
+	  half_mode = V2SImode;
 	  break;
 	case E_V4SFmode:
-	  cmode = V2SFmode;
+	  half_mode = V2SFmode;
 	  break;
 	default:
 	  gcc_unreachable ();
@@ -13742,20 +13742,16 @@ ix86_expand_vector_init_concat (machine_mode mode,
       switch (mode)
 	{
 	case E_V8DImode:
-	  cmode = V2DImode;
-	  hmode = V4DImode;
+	  half_mode = V4DImode;
 	  break;
 	case E_V8DFmode:
-	  cmode = V2DFmode;
-	  hmode = V4DFmode;
+	  half_mode = V4DFmode;
 	  break;
 	case E_V8SImode:
-	  cmode = V2SImode;
-	  hmode = V4SImode;
+	  half_mode = V4SImode;
 	  break;
 	case E_V8SFmode:
-	  cmode = V2SFmode;
-	  hmode = V4SFmode;
+	  half_mode = V4SFmode;
 	  break;
 	default:
 	  gcc_unreachable ();
@@ -13766,14 +13762,10 @@ ix86_expand_vector_init_concat (machine_mode mode,
       switch (mode)
 	{
 	case E_V16SImode:
-	  cmode = V2SImode;
-	  hmode = V4SImode;
-	  gmode = V8SImode;
+	  half_mode = V8SImode;
 	  break;
 	case E_V16SFmode:
-	  cmode = V2SFmode;
-	  hmode = V4SFmode;
-	  gmode = V8SFmode;
+	  half_mode = V8SFmode;
 	  break;
 	default:
 	  gcc_unreachable ();
@@ -13783,50 +13775,32 @@ ix86_expand_vector_init_concat (machine_mode mode,
 half:
       /* FIXME: We process inputs backward to help RA.  PR 36222.  */
       i = n - 1;
-      j = (n >> 1) - 1;
-      for (; i > 0; i -= 2, j--)
-	{
-	  first[j] = gen_reg_rtx (cmode);
-	  v = gen_rtvec (2, ops[i - 1], ops[i]);
-	  ix86_expand_vector_init (false, first[j],
-				   gen_rtx_PARALLEL (cmode, v));
-	}
-
-      n >>= 1;
-      if (n > 4)
-	{
-	  gcc_assert (hmode != VOIDmode);
-	  gcc_assert (gmode != VOIDmode);
-	  for (i = j = 0; i < n; i += 2, j++)
-	    {
-	      second[j] = gen_reg_rtx (hmode);
-	      ix86_expand_vector_init_concat (hmode, second [j],
-					      &first [i], 2);
-	    }
-	  n >>= 1;
-	  for (i = j = 0; i < n; i += 2, j++)
-	    {
-	      third[j] = gen_reg_rtx (gmode);
-	      ix86_expand_vector_init_concat (gmode, third[j],
-					      &second[i], 2);
-	    }
-	  n >>= 1;
-	  ix86_expand_vector_init_concat (mode, target, third, n);
-	}
-      else if (n > 2)
+      for (j = 1; j != -1; j--)
 	{
-	  gcc_assert (hmode != VOIDmode);
-	  for (i = j = 0; i < n; i += 2, j++)
+	  half[j] = gen_reg_rtx (half_mode);
+	  switch (n >> 1)
 	    {
-	      second[j] = gen_reg_rtx (hmode);
-	      ix86_expand_vector_init_concat (hmode, second [j],
-					      &first [i], 2);
+	    case 2:
+	      v = gen_rtvec (2, ops[i-1], ops[i]);
+	      i -= 2;
+	      break;
+	    case 4:
+	      v = gen_rtvec (4, ops[i-3], ops[i-2], ops[i-1], ops[i]);
+	      i -= 4;
+	      break;
+	    case 8:
+	      v = gen_rtvec (8, ops[i-7], ops[i-6], ops[i-5], ops[i-4],
+			     ops[i-3], ops[i-2], ops[i-1], ops[i]);
+	      i -= 8;
+	      break;
+	    default:
+	      gcc_unreachable ();
 	    }
-	  n >>= 1;
-	  ix86_expand_vector_init_concat (mode, target, second, n);
+	  ix86_expand_vector_init (false, half[j],
+				   gen_rtx_PARALLEL (half_mode, v));
 	}
-      else
-	ix86_expand_vector_init_concat (mode, target, first, n);
+
+      ix86_expand_vector_init_concat (mode, target, half, 2);
       break;
 
     default:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 459fd89..dec8948 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2019-11-08  Hongtao Liu  <hongtao.liu@intel.com>
+
+	* gcc.target/i386/pr92295.c: New test.
+
 2019-11-08  Joseph Myers  <joseph@codesourcery.com>
 
 	* gcc.dg/c11-old-style-definition-1.c,
diff --git a/gcc/testsuite/gcc.target/i386/pr92295.c b/gcc/testsuite/gcc.target/i386/pr92295.c
new file mode 100644
index 0000000..179dc48
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr92295.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=skylake-avx512" } */
+
+typedef int X __attribute__((vector_size (32)));
+
+X
+foo (int x, int z)
+{
+  X y = { x, x, x, x, z, z, z, z };
+  return y;
+}
+
+/* { dg-final { scan-assembler-times "vpbroadcast" "2" } } */