X86: Properly decode shuffle masks when the constant pool type is weird

It's possible for the constant pool entry for the shuffle mask to come
from a completely different operation.  This occurs when Constants have
the same bit pattern but have different types.

Make DecodePSHUFBMask tolerant of types which, after a bitcast, are
appropriately sized vector types.

This fixes PR22188.

llvm-svn: 225597

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
index 6ba3c64f8ec..48ba32354f9 100644
--- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
+++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.h
@@ -24,6 +24,7 @@
 
 namespace llvm {
 class Constant;
+class DataLayout;
 class MVT;
 
 enum { SM_SentinelUndef = -1, SM_SentinelZero = -2 };
@@ -68,7 +69,8 @@ void DecodeUNPCKHMask(MVT VT, SmallVectorImpl<int> &ShuffleMask);
 void DecodeUNPCKLMask(MVT VT, SmallVectorImpl<int> &ShuffleMask);
 
 /// \brief Decode a PSHUFB mask from an IR-level vector constant.
-void DecodePSHUFBMask(const Constant *C, SmallVectorImpl<int> &ShuffleMask);
+void DecodePSHUFBMask(const Constant *C, const DataLayout *TD,
+                      SmallVectorImpl<int> &ShuffleMask);
 
 /// \brief Decode a PSHUFB mask from a raw array of constants such as from
 /// BUILD_VECTOR.