[x86] Hoist the zext-lowering up in the v4i32 lowering routine -- it is

the same speed as pshufd but we can fold loads into the pmovzx
instructions.

This fixes some regressions that came up in the regression test suite
for the new vector shuffle lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218733 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 394a62210561dd9007141514ba85d4baf6d244be..947cd01308bf199ec908924d051afc0f46b7d73d 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -8214,6 +8214,13 @@ static SDValue lowerV4I32VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
   ArrayRef<int> Mask = SVOp->getMask();
   assert(Mask.size() == 4 && "Unexpected mask size for v4 shuffle!");
 
+  // Whenever we can lower this as a zext, that instruction is strictly faster
+  // than any alternative. It also allows us to fold memory operansd into the
+  // shuffle in many cases.
+  if (SDValue ZExt = lowerVectorShuffleAsZeroOrAnyExtend(DL, MVT::v4i32, V1, V2,
+                                                         Mask, Subtarget, DAG))
+    return ZExt;
+
   int NumV2Elements =
       std::count_if(Mask.begin(), Mask.end(), [](int M) { return M >= 4; });
 
@@ -8239,12 +8246,6 @@ static SDValue lowerV4I32VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
                        getV4X86ShuffleImm8ForMask(Mask, DAG));
   }
 
-  // Whenever we can lower this as a zext, that instruction is strictly faster
-  // than any alternative.
-  if (SDValue ZExt = lowerVectorShuffleAsZeroOrAnyExtend(DL, MVT::v4i32, V1, V2,
-                                                         Mask, Subtarget, DAG))
-    return ZExt;
-
   // Use dedicated unpack instructions for masks that match their pattern.
   if (isShuffleEquivalent(Mask, 0, 4, 1, 5))
     return DAG.getNode(X86ISD::UNPCKL, DL, MVT::v4i32, V1, V2);

diff --git a/test/CodeGen/X86/vector-shuffle-128-v4.ll b/test/CodeGen/X86/vector-shuffle-128-v4.ll
index 080cd439476656e4dcd243640458803d5a61b454..948f1d2e47afa04522f4944f5284d2dc8ea0d630 100644 (file)
--- a/test/CodeGen/X86/vector-shuffle-128-v4.ll
+++ b/test/CodeGen/X86/vector-shuffle-128-v4.ll
@@ -937,14 +937,29 @@ define <4 x i32> @shuffle_v4i32_3456(<4 x i32> %a, <4 x i32> %b) {
 }
 
 define <4 x i32> @shuffle_v4i32_0u1u(<4 x i32> %a, <4 x i32> %b) {
-; SSE-LABEL: shuffle_v4i32_0u1u:
-; SSE:       # BB#0:
-; SSE-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,0,1,1]
-; SSE-NEXT:    retq
+; SSE2-LABEL: shuffle_v4i32_0u1u:
+; SSE2:       # BB#0:
+; SSE2-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,1,1,3]
+; SSE2-NEXT:    retq
+;
+; SSE3-LABEL: shuffle_v4i32_0u1u:
+; SSE3:       # BB#0:
+; SSE3-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,1,1,3]
+; SSE3-NEXT:    retq
+;
+; SSSE3-LABEL: shuffle_v4i32_0u1u:
+; SSSE3:       # BB#0:
+; SSSE3-NEXT:    pshufd {{.*#+}} xmm0 = xmm0[0,1,1,3]
+; SSSE3-NEXT:    retq
+;
+; SSE41-LABEL: shuffle_v4i32_0u1u:
+; SSE41:       # BB#0:
+; SSE41-NEXT:    pmovzxdq %xmm0, %xmm0
+; SSE41-NEXT:    retq
 ;
 ; AVX-LABEL: shuffle_v4i32_0u1u:
 ; AVX:       # BB#0:
-; AVX-NEXT:    vpshufd {{.*#+}} xmm0 = xmm0[0,0,1,1]
+; AVX-NEXT:    vpmovzxdq %xmm0, %xmm0
 ; AVX-NEXT:    retq
   %shuffle = shufflevector <4 x i32> %a, <4 x i32> %b, <4 x i32> <i32 0, i32 undef, i32 1, i32 undef>
   ret <4 x i32> %shuffle