8c5c5a01e5
Merge commit e8305c0b8f49 from llvm git (by Simon Pilgrim)
[X86] combineX86ShuffleChain - don't fold to truncate(concat(V1,V2)) if it was already a PACK op
Fixes #55050
PR: 264480
MFH: 2022Q3
Sponsored by: DARPA, AFRL
15 lines
864 B
C++
15 lines
864 B
C++
--- lib/Target/X86/X86ISelLowering.cpp.orig
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+++ lib/Target/X86/X86ISelLowering.cpp
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@@ -36201,7 +36201,11 @@
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(RootVT.is128BitVector() && Subtarget.hasVLX())) &&
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(MaskEltSizeInBits > 8 || Subtarget.hasBWI()) &&
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isSequentialOrUndefInRange(Mask, 0, NumMaskElts, 0, 2)) {
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- if (Depth == 0 && Root.getOpcode() == ISD::TRUNCATE)
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+ // Bail if this was already a truncation or PACK node.
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+ // We sometimes fail to match PACK if we demand known undef elements.
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+ if (Depth == 0 && (Root.getOpcode() == ISD::TRUNCATE ||
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+ Root.getOpcode() == X86ISD::PACKSS ||
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+ Root.getOpcode() == X86ISD::PACKUS))
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return SDValue(); // Nothing to do!
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ShuffleSrcVT = MVT::getIntegerVT(MaskEltSizeInBits * 2);
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ShuffleSrcVT = MVT::getVectorVT(ShuffleSrcVT, NumMaskElts / 2);
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