diff options
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp | 10 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/pshufb-mask-comments.ll | 30 |
2 files changed, 34 insertions, 6 deletions
diff --git a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp index 51d251e551c..6d42a101b0e 100644 --- a/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp +++ b/llvm/lib/Target/X86/Utils/X86ShuffleDecode.cpp @@ -247,9 +247,8 @@ void DecodePSHUFBMask(const ConstantDataSequential *C, if (Element & (1 << 7)) ShuffleMask.push_back(SM_SentinelZero); else { - int Index = Base + Element; - assert((Index >= 0 && Index < NumElements) && - "Out of bounds shuffle index for pshub instruction!"); + // Only the least significant 4 bits of the byte are used. + int Index = Base + (Element & 0xf); ShuffleMask.push_back(Index); } } @@ -266,9 +265,8 @@ void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask, if (M & (1 << 7)) ShuffleMask.push_back(SM_SentinelZero); else { - int Index = Base + M; - assert((Index >= 0 && (unsigned)Index < RawMask.size()) && - "Out of bounds shuffle index for pshub instruction!"); + // Only the least significant 4 bits of the byte are used. + int Index = Base + (M & 0xf); ShuffleMask.push_back(Index); } } diff --git a/llvm/test/CodeGen/X86/pshufb-mask-comments.ll b/llvm/test/CodeGen/X86/pshufb-mask-comments.ll new file mode 100644 index 00000000000..3c5d6d6864a --- /dev/null +++ b/llvm/test/CodeGen/X86/pshufb-mask-comments.ll @@ -0,0 +1,30 @@ +; RUN: llc < %s -march=x86-64 -mattr=+ssse3 | FileCheck %s + +; Test that the pshufb mask comment is correct. + +define <16 x i8> @test1(<16 x i8> %V) { +; CHECK-LABEL: test1: +; CHECK: pshufb {{.*}} # xmm0 = xmm0[1,0,0,0,0,2,0,0,0,0,3,0,0,0,0,4] + %1 = tail call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> %V, <16 x i8> <i8 1, i8 0, i8 0, i8 0, i8 0, i8 2, i8 0, i8 0, i8 0, i8 0, i8 3, i8 0, i8 0, i8 0, i8 0, i8 4>) + ret <16 x i8> %1 +} + +; Test that indexes larger than the size of the vector are shown masked (bottom 4 bits). + +define <16 x i8> @test2(<16 x i8> %V) { +; CHECK-LABEL: test2: +; CHECK: pshufb {{.*}} # xmm0 = xmm0[15,0,0,0,0,0,0,0,0,0,1,0,0,0,0,2] + %1 = tail call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> %V, <16 x i8> <i8 15, i8 0, i8 0, i8 0, i8 0, i8 16, i8 0, i8 0, i8 0, i8 0, i8 17, i8 0, i8 0, i8 0, i8 0, i8 50>) + ret <16 x i8> %1 +} + +; Test that indexes with bit seven set are shown as zero. + +define <16 x i8> @test3(<16 x i8> %V) { +; CHECK-LABEL: test3: +; CHECK: pshufb {{.*}} # xmm0 = xmm0[1,0,0,15,0,2,0,0],zero,xmm0[0,3,0,0],zero,xmm0[0,4] + %1 = tail call <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8> %V, <16 x i8> <i8 1, i8 0, i8 0, i8 127, i8 0, i8 2, i8 0, i8 0, i8 128, i8 0, i8 3, i8 0, i8 0, i8 255, i8 0, i8 4>) + ret <16 x i8> %1 +} + +declare <16 x i8> @llvm.x86.ssse3.pshuf.b.128(<16 x i8>, <16 x i8>) nounwind readnone |
