From a96d62b360b873046035ba439053cd4de2ff1470 Mon Sep 17 00:00:00 2001 From: Craig Topper Date: Sat, 4 Nov 2017 06:44:47 +0000 Subject: [X86] Teach shuffle lowering to use 256-bit SHUF128 when possible. This allows masked operations to be used and allows the register allocator to use YMM16-31 if necessary. As a follow up I'll look into teaching EVEX->VEX how to turn this back into PERM2X128 if any of the additional features don't work out. llvm-svn: 317403 --- llvm/lib/Target/X86/X86ISelLowering.cpp | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'llvm/lib/Target/X86/X86ISelLowering.cpp') diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp index ea97dc2dccd..3883415501b 100644 --- a/llvm/lib/Target/X86/X86ISelLowering.cpp +++ b/llvm/lib/Target/X86/X86ISelLowering.cpp @@ -12384,6 +12384,16 @@ static SDValue lowerV2X128VectorShuffle(const SDLoc &DL, MVT VT, SDValue V1, return DAG.getNode(ISD::CONCAT_VECTORS, DL, VT, LoV, HiV); } } + + // Try to use SHUF128 if possible. + if (Subtarget.hasVLX()) { + if (WidenedMask[0] < 2 && WidenedMask[1] >= 2) { + unsigned PermMask = ((WidenedMask[0] % 2) << 0) | + ((WidenedMask[1] % 2) << 1); + return DAG.getNode(X86ISD::SHUF128, DL, VT, V1, V2, + DAG.getConstant(PermMask, DL, MVT::i8)); + } + } } // Otherwise form a 128-bit permutation. After accounting for undefs, -- cgit v1.2.3