From c5114dbcc3cd5a768bed43e5ae88d87a88b4a1b1 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Fri, 27 Jun 2014 11:40:13 +0000
Subject: [x86] Teach the target combine step to aggressively fold pshufd
 insturcions.

Summary:
This allows it to fold pshufd instructions across intervening
half-shuffles and other noise. This pattern actually shows up in the
generic lowering tests, but I've also added direct tests using
intrinsics to make sure that the specific desired functionality is
working even if the lowering stuff changes in the future.

Differential Revision: http://reviews.llvm.org/D4292

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@211892 91177308-0d34-0410-b5e6-96231b3b80d8
---
 test/CodeGen/X86/vector-shuffle-128-v8.ll    |  3 +-
 test/CodeGen/X86/vector-shuffle-combining.ll | 60 ++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+), 2 deletions(-)

(limited to 'test')

diff --git a/test/CodeGen/X86/vector-shuffle-128-v8.ll b/test/CodeGen/X86/vector-shuffle-128-v8.ll
index 091822b6cb..5d1922a348 100644
--- a/test/CodeGen/X86/vector-shuffle-128-v8.ll
+++ b/test/CodeGen/X86/vector-shuffle-128-v8.ll
@@ -157,9 +157,8 @@ define <8 x i16> @shuffle_v8i16_26401375(<8 x i16> %a, <8 x i16> %b) {
 ; CHECK-SSE2:       # BB#0:
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[0,2,1,3,4,5,6,7]
 ; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,7,5,4,6]
-; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,3,2,1]
+; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,3,1,2]
 ; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[1,3,2,0,4,5,6,7]
-; CHECK-SSE2-NEXT:    pshufd {{.*}} # xmm0 = xmm0[0,1,3,2]
 ; CHECK-SSE2-NEXT:    retq
   %shuffle = shufflevector <8 x i16> %a, <8 x i16> %b, <8 x i32> <i32 2, i32 6, i32 4, i32 0, i32 1, i32 3, i32 7, i32 5>
   ret <8 x i16> %shuffle
diff --git a/test/CodeGen/X86/vector-shuffle-combining.ll b/test/CodeGen/X86/vector-shuffle-combining.ll
index dae1ef5875..1bc2aee6ef 100644
--- a/test/CodeGen/X86/vector-shuffle-combining.ll
+++ b/test/CodeGen/X86/vector-shuffle-combining.ll
@@ -3,9 +3,69 @@
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-unknown"
 
+declare <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32>, i8)
 declare <8 x i16> @llvm.x86.sse2.pshufl.w(<8 x i16>, i8)
 declare <8 x i16> @llvm.x86.sse2.pshufh.w(<8 x i16>, i8)
 
+define <4 x i32> @combine_pshufd1(<4 x i32> %a) {
+; CHECK-SSE2-LABEL: @combine_pshufd1
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    retq
+  %b = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %a, i8 27) 
+  %c = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %b, i8 27) 
+  ret <4 x i32> %c
+}
+
+define <4 x i32> @combine_pshufd2(<4 x i32> %a) {
+; CHECK-SSE2-LABEL: @combine_pshufd2
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    retq
+  %b = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %a, i8 27) 
+  %b.cast = bitcast <4 x i32> %b to <8 x i16>
+  %c = call <8 x i16> @llvm.x86.sse2.pshufl.w(<8 x i16> %b.cast, i8 -28)
+  %c.cast = bitcast <8 x i16> %c to <4 x i32>
+  %d = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %c.cast, i8 27) 
+  ret <4 x i32> %d
+}
+
+define <4 x i32> @combine_pshufd3(<4 x i32> %a) {
+; CHECK-SSE2-LABEL: @combine_pshufd3
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    retq
+  %b = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %a, i8 27) 
+  %b.cast = bitcast <4 x i32> %b to <8 x i16>
+  %c = call <8 x i16> @llvm.x86.sse2.pshufh.w(<8 x i16> %b.cast, i8 -28)
+  %c.cast = bitcast <8 x i16> %c to <4 x i32>
+  %d = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %c.cast, i8 27) 
+  ret <4 x i32> %d
+}
+
+define <4 x i32> @combine_pshufd4(<4 x i32> %a) {
+; CHECK-SSE2-LABEL: @combine_pshufd4
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    pshufhw {{.*}} # xmm0 = xmm0[0,1,2,3,7,6,5,4]
+; CHECK-SSE2-NEXT:    retq
+  %b = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %a, i8 -31) 
+  %b.cast = bitcast <4 x i32> %b to <8 x i16>
+  %c = call <8 x i16> @llvm.x86.sse2.pshufh.w(<8 x i16> %b.cast, i8 27)
+  %c.cast = bitcast <8 x i16> %c to <4 x i32>
+  %d = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %c.cast, i8 -31) 
+  ret <4 x i32> %d
+}
+
+define <4 x i32> @combine_pshufd5(<4 x i32> %a) {
+; CHECK-SSE2-LABEL: @combine_pshufd5
+; CHECK-SSE2:       # BB#0:
+; CHECK-SSE2-NEXT:    pshuflw {{.*}} # xmm0 = xmm0[3,2,1,0,4,5,6,7]
+; CHECK-SSE2-NEXT:    retq
+  %b = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %a, i8 -76) 
+  %b.cast = bitcast <4 x i32> %b to <8 x i16>
+  %c = call <8 x i16> @llvm.x86.sse2.pshufl.w(<8 x i16> %b.cast, i8 27)
+  %c.cast = bitcast <8 x i16> %c to <4 x i32>
+  %d = call <4 x i32> @llvm.x86.sse2.pshuf.d(<4 x i32> %c.cast, i8 -76)
+  ret <4 x i32> %d
+}
+
 define <8 x i16> @combine_pshuflw1(<8 x i16> %a) {
 ; CHECK-SSE2-LABEL: @combine_pshuflw1
 ; CHECK-SSE2:       # BB#0:
-- 
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