Allow to fold vector load if there is more than one bitcast, so in the case:

%0 = load <8 x i16>* %dest
%1 = shufflevector <8 x i16> %0, <8 x i16> %in,
      <8 x i32> < i32 0, i32 1, i32 2, i32 3, i32 13, i32 undef, i32 14, i32 14>
store <8 x i16> %1, <8 x i16>* %dest

We get:
  vmovlpd (%eax), %xmm0, %xmm0

instead of:
  vmovaps (%eax), %xmm1
  vmovsd  %xmm1, %xmm0, %xmm0

No extra test-case is added. I just fixed the existing one
(also it uses FileCheck now).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166971 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 13 insertions, 9 deletions

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 06b83297fe..b65fcf1bbe 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -6438,17 +6438,17 @@ LowerVECTOR_SHUFFLE_128v4(ShuffleVectorSDNode *SVOp, SelectionDAG &DAG) {
 }
 
 static bool MayFoldVectorLoad(SDValue V) {
-  if (V.hasOneUse() && V.getOpcode() == ISD::BITCAST)
+  while (V.hasOneUse() && V.getOpcode() == ISD::BITCAST)
     V = V.getOperand(0);
+
   if (V.hasOneUse() && V.getOpcode() == ISD::SCALAR_TO_VECTOR)
     V = V.getOperand(0);
   if (V.hasOneUse() && V.getOpcode() == ISD::BUILD_VECTOR &&
       V.getNumOperands() == 2 && V.getOperand(1).getOpcode() == ISD::UNDEF)
     // BUILD_VECTOR (load), undef
     V = V.getOperand(0);
-  if (MayFoldLoad(V))
-    return true;
-  return false;
+
+  return MayFoldLoad(V);
 }
 
 // FIXME: the version above should always be used. Since there's
diff --git a/test/CodeGen/X86/vec_shuffle-30.ll b/test/CodeGen/X86/vec_shuffle-30.ll
index 1651c4cdac..3ae3b356fe 100644
--- a/test/CodeGen/X86/vec_shuffle-30.ll
+++ b/test/CodeGen/X86/vec_shuffle-30.ll
@@ -1,21 +1,25 @@
-; RUN: llc < %s -march=x86 -mattr=sse41 -o %t
-; RUN: grep pshufhw %t | grep -- -95 | count 1
-; RUN: grep shufps %t | count 1
-; RUN: not grep pslldq %t
+; RUN: llc < %s -march=x86 -mattr=sse41 | FileCheck %s
 
+; CHECK: test
 ; Test case when creating pshufhw, we incorrectly set the higher order bit
 ; for an undef,
 define void @test(<8 x i16>* %dest, <8 x i16> %in) nounwind {
 entry:
+; CHECK-NOT: vmovaps
+; CHECK: vmovlpd
+; CHECK: vpshufhw        $-95
   %0 = load <8 x i16>* %dest
   %1 = shufflevector <8 x i16> %0, <8 x i16> %in, <8 x i32> < i32 0, i32 1, i32 2, i32 3, i32 13, i32 undef, i32 14, i32 14>
   store <8 x i16> %1, <8 x i16>* %dest
   ret void
-}                              
+}
 
+; CHECK: test2
 ; A test case where we shouldn't generate a punpckldq but a pshufd and a pslldq
 define void @test2(<4 x i32>* %dest, <4 x i32> %in) nounwind {
 entry:
+; CHECK-NOT: pslldq
+; CHECK: shufps
   %0 = shufflevector <4 x i32> %in, <4 x i32> <i32 0, i32 0, i32 0, i32 0>, <4 x i32> < i32 undef, i32 5, i32 undef, i32 2>
   store <4 x i32> %0, <4 x i32>* %dest
   ret void