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X86: Don't crash if we can't decode the pshufb mask 

Constant pool entries are uniqued by their contents regardless of their
type.  This means that a pshufb can have a shuffle mask which isn't a
simple array of bytes.

The code path which attempts to decode the mask didn't check for
failure, causing PR22559.

llvm-svn: 228979
This commit is contained in:
David Majnemer 2015-02-12 23:26:26 +00:00
parent 8807e83037
commit a12fcb790f
2 changed files with 14 additions and 0 deletions
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2
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -5480,6 +5480,8 @@ static bool getTargetShuffleMask(SDNode *N, MVT VT,
if (auto *C = dyn_cast<Constant>(MaskCP->getConstVal())) {
DecodePSHUFBMask(C, Mask);
if (Mask.empty())
return false;
break;
}

12
llvm/test/CodeGen/X86/pshufb-mask-comments.ll
View File

@ -37,4 +37,16 @@ define <16 x i8> @test4(<2 x i64>* %V) {
ret <16 x i8> %1
}
define <16 x i8> @test5() {
; CHECK-LABEL: test5
; CHECK: pshufb {{.*}}
store <2 x i64> <i64 1, i64 0>, <2 x i64>* undef, align 16
%l = load <2 x i64>* undef, align 16
%shuffle = shufflevector <2 x i64> %l, <2 x i64> undef, <2 x i32> zeroinitializer
store <2 x i64> %shuffle, <2 x i64>* undef, align 16
%1 = load <16 x i8>* undef, align 16
%2 = call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> undef, <16 x i8> %1)
ret <16 x i8> %2
}
declare <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8>, <16 x i8>) nounwind readnone