From 8336fc6508b3aad3cff0c2c022bb91dc269ebc05 Mon Sep 17 00:00:00 2001 From: Simon Pilgrim Date: Fri, 10 Feb 2017 13:16:01 +0000 Subject: [PATCH] [X86][SSE] Add missing comment describing combing to SHUFPS. NFCI git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294745 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86ISelLowering.cpp | 2 ++ 1 file changed, 2 insertions(+) diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index 86b78fe5193..4fddf3ff1d6 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -26759,6 +26759,8 @@ static bool matchBinaryPermuteVectorShuffle(MVT MaskVT, ArrayRef Mask, (MaskVT == MVT::v16f32 && Subtarget.hasAVX512())) { SmallVector RepeatedMask; if (isRepeatedTargetShuffleMask(128, MaskVT, Mask, RepeatedMask)) { + // Match each half of the repeated mask, to determine if its just + // referencing one of the vectors, is zeroable or entirely undef. auto MatchHalf = [&](unsigned Offset, int &S0, int &S1) { int M0 = RepeatedMask[Offset]; int M1 = RepeatedMask[Offset + 1]; -- 2.11.0