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x86: Add 3-instruction subroutine vector shift for V16QI in ix86_expand_vec_perm_const_1 [PR107563]

Message ID 20240514090454.3966366-1-admin@levyhsu.com
State New
Headers show
Series x86: Add 3-instruction subroutine vector shift for V16QI in ix86_expand_vec_perm_const_1 [PR107563] | expand

Commit Message

Levy Hsu May 14, 2024, 9:04 a.m. UTC 
Hi All

We've introduced a new subroutine in ix86_expand_vec_perm_const_1
to optimize vector shifting for the V16QI type on x86.
This patch uses a three-instruction sequence psrlw, psllw, and por
to handle specific vector shuffle operations more efficiently.
The change aims to improve assembly code generation for configurations
supporting SSE2.

Bootstrapped and tested on x86_64-linux-gnu, OK for trunk?

Best
Levy

gcc/ChangeLog:

	PR target/107563
	* config/i386/i386-expand.cc (expand_vec_perm_psrlw_psllw_por): New
	subroutine.
	(ix86_expand_vec_perm_const_1): Call expand_vec_perm_psrlw_psllw_por.

gcc/testsuite/ChangeLog:

	PR target/107563
	* g++.target/i386/pr107563-a.C: New test.
	* g++.target/i386/pr107563-b.C: New test.
---
 gcc/config/i386/i386-expand.cc             | 64 ++++++++++++++++++++++
 gcc/testsuite/g++.target/i386/pr107563-a.C | 13 +++++
 gcc/testsuite/g++.target/i386/pr107563-b.C | 12 ++++
 3 files changed, 89 insertions(+)
 create mode 100755 gcc/testsuite/g++.target/i386/pr107563-a.C
 create mode 100755 gcc/testsuite/g++.target/i386/pr107563-b.C
diff mbox series

Patch

diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 2f27bfb484c..5098d2886bb 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -22362,6 +22362,67 @@  expand_vec_perm_2perm_pblendv (struct expand_vec_perm_d *d, bool two_insn)
   return true;
 }
 
+/* A subroutine of ix86_expand_vec_perm_const_1.
+   Implement a permutation with psrlw, psllw and por.
+   It handles case:
+   __builtin_shufflevector (v,v,1,0,3,2,5,4,7,6,9,8,11,10,13,12,15,14);
+   __builtin_shufflevector (v,v,1,0,3,2,5,4,7,6); */
+
+static bool
+expand_vec_perm_psrlw_psllw_por (struct expand_vec_perm_d *d)
+{
+  unsigned i;
+  rtx (*gen_shr) (rtx, rtx, rtx);
+  rtx (*gen_shl) (rtx, rtx, rtx);
+  rtx (*gen_or) (rtx, rtx, rtx);
+  machine_mode mode = VOIDmode;
+
+  if (!TARGET_SSE2 || !d->one_operand_p)
+    return false;
+
+  switch (d->vmode)
+    {
+    case E_V8QImode:
+      if (!TARGET_MMX_WITH_SSE)
+	return false;
+      mode = V4HImode;
+      gen_shr = gen_ashrv4hi3;
+      gen_shl = gen_ashlv4hi3;
+      gen_or = gen_iorv4hi3;
+      break;
+    case E_V16QImode:
+      mode = V8HImode;
+      gen_shr = gen_vlshrv8hi3;
+      gen_shl = gen_vashlv8hi3;
+      gen_or = gen_iorv8hi3;
+      break;
+    default: return false;
+    }
+
+  if (!rtx_equal_p (d->op0, d->op1))
+    return false;
+
+  for (i = 0; i < d->nelt; i += 2)
+    if (d->perm[i] != i + 1 || d->perm[i + 1] != i)
+      return false;
+
+  if (d->testing_p)
+    return true;
+
+  rtx tmp1 = gen_reg_rtx (mode);
+  rtx tmp2 = gen_reg_rtx (mode);
+  rtx op0 = force_reg (d->vmode, d->op0);
+
+  emit_move_insn (tmp1, lowpart_subreg (mode, op0, d->vmode));
+  emit_move_insn (tmp2, lowpart_subreg (mode, op0, d->vmode));
+  emit_insn (gen_shr (tmp1, tmp1, GEN_INT (8)));
+  emit_insn (gen_shl (tmp2, tmp2, GEN_INT (8)));
+  emit_insn (gen_or (tmp1, tmp1, tmp2));
+  emit_move_insn (d->target, lowpart_subreg (d->vmode, tmp1, mode));
+
+  return true;
+}
+
 /* A subroutine of ix86_expand_vec_perm_const_1.  Implement a V4DF
    permutation using two vperm2f128, followed by a vshufpd insn blending
    the two vectors together.  */
@@ -23782,6 +23843,9 @@  ix86_expand_vec_perm_const_1 (struct expand_vec_perm_d *d)
   if (expand_vec_perm_2perm_pblendv (d, false))
     return true;
 
+  if (expand_vec_perm_psrlw_psllw_por (d))
+    return true;
+
   /* Try sequences of four instructions.  */
 
   if (expand_vec_perm_even_odd_trunc (d))
diff --git a/gcc/testsuite/g++.target/i386/pr107563-a.C b/gcc/testsuite/g++.target/i386/pr107563-a.C
new file mode 100755
index 00000000000..605c1bdf814
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr107563-a.C
@@ -0,0 +1,13 @@ 
+/* PR target/107563.C */
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-std=c++2b -O3 -msse2" } */
+/* { dg-final { scan-assembler-times "psllw" 1 } } */
+/* { dg-final { scan-assembler-times "psraw" 1 } } */
+/* { dg-final { scan-assembler-times "por" 1 } } */
+
+using temp_vec_type2 [[__gnu__::__vector_size__(8)]] = char;
+
+void foo2(temp_vec_type2& v) noexcept
+{
+  v = __builtin_shufflevector(v, v, 1, 0, 3, 2, 5, 4, 7, 6);
+}
diff --git a/gcc/testsuite/g++.target/i386/pr107563-b.C b/gcc/testsuite/g++.target/i386/pr107563-b.C
new file mode 100755
index 00000000000..0ce3e8263bb
--- /dev/null
+++ b/gcc/testsuite/g++.target/i386/pr107563-b.C
@@ -0,0 +1,12 @@ 
+/* PR target/107563.C */
+/* { dg-options "-std=c++2b -O3 -msse2" } */
+/* { dg-final { scan-assembler-times "psllw" 1 } } */
+/* { dg-final { scan-assembler-times "psrlw" 1 } } */
+/* { dg-final { scan-assembler-times "por" 1 } } */
+
+using temp_vec_type [[__gnu__::__vector_size__(16)]] = char;
+
+void foo(temp_vec_type& v) noexcept
+{
+  v = __builtin_shufflevector(v, v, 1, 0, 3, 2, 5, 4, 7, 6, 9, 8, 11, 10, 13, 12, 15, 14);
+}