[x86] Fix another bug hit when bootstrapping with the new shuffle

lowering.

For maximum irony, I had already discovered this bug, diagnosed it, and
left FIXMEs about it in the test cases. =[ I just failed to go back over
those until after i had reduced a bootstrap miscompile down to a single
TU, stared at the assembly for an hour, and figured out the bug. Again.

Oh well.

llvm-svn: 211955

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index fa80717f994..b77a7fee0b7 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -7105,7 +7105,7 @@ static SDValue lowerV4F32VectorShuffle(SDValue Op, SDValue V1, SDValue V2,
 
       // Now we do a normal shuffle of V1 by giving V1 as both operands to
       // a blend.
-      HighV = V1;
+      LowV = HighV = V1;
       NewMask[0] = Mask[0] < 4 ? 0 : 2;
       NewMask[1] = Mask[0] < 4 ? 2 : 0;
       NewMask[2] = Mask[2] < 4 ? 1 : 3;