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[X86] isGuaranteedNotToBeUndefOrPoison - add simple target shuffles with known test coverage (#161553)

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Add a number of simple target shuffles (fixed shuffle mask or simple
immediate control) to
isGuaranteedNotToBeUndefOrPoison/canCreateUndefOrPoisonForTargetNode
that have known test coverage and obviously don't introduce
undef/poison.

These were found by adding an assert for unhandled target shuffles and
running over CodeGen/X86 - providing explicit test coverage is
incredibly difficult as ISD::VECTOR_SHUFFLE nodes will typically handle
freeze nodes before we lower to these target shuffle nodes.
This commit is contained in:
Simon Pilgrim
2025-11-07 17:22:50 +00:00
committed by GitHub
parent a3b5b4bd79
commit 626cbf70f1
1 changed files with 21 additions and 0 deletions
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21
llvm/lib/Target/X86/X86ISelLowering.cpp
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@@ -45022,11 +45022,16 @@ bool X86TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode(
case X86ISD::INSERTPS:
case X86ISD::BLENDI:
case X86ISD::PSHUFB:
case X86ISD::VZEXT_MOVL:
case X86ISD::PSHUFD:
case X86ISD::PSHUFHW:
case X86ISD::PSHUFLW:
case X86ISD::SHUFP:
case X86ISD::UNPCKL:
case X86ISD::UNPCKH:
case X86ISD::VPERMILPV:
case X86ISD::VPERMILPI:
case X86ISD::VPERMI:
case X86ISD::VPERMV:
case X86ISD::VPERMV3: {
SmallVector<int, 8> Mask;
@@ -45052,6 +45057,16 @@ bool X86TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode(
}
break;
}
case X86ISD::VBROADCAST: {
SDValue Src = Op.getOperand(0);
MVT SrcVT = Src.getSimpleValueType();
if (SrcVT.isVector()) {
APInt DemandedSrc = APInt::getOneBitSet(SrcVT.getVectorNumElements(), 0);
return DAG.isGuaranteedNotToBeUndefOrPoison(Src, DemandedSrc, PoisonOnly,
Depth + 1);
}
return DAG.isGuaranteedNotToBeUndefOrPoison(Src, PoisonOnly, Depth + 1);
}
}
return TargetLowering::isGuaranteedNotToBeUndefOrPoisonForTargetNode(
Op, DemandedElts, DAG, PoisonOnly, Depth);
@@ -45096,13 +45111,19 @@ bool X86TargetLowering::canCreateUndefOrPoisonForTargetNode(
// SSE target shuffles.
case X86ISD::INSERTPS:
case X86ISD::PSHUFB:
case X86ISD::VZEXT_MOVL:
case X86ISD::PSHUFD:
case X86ISD::PSHUFHW:
case X86ISD::PSHUFLW:
case X86ISD::SHUFP:
case X86ISD::UNPCKL:
case X86ISD::UNPCKH:
case X86ISD::VPERMILPV:
case X86ISD::VPERMILPI:
case X86ISD::VPERMI:
case X86ISD::VPERMV:
case X86ISD::VPERMV3:
case X86ISD::VBROADCAST:
return false;
// SSE comparisons handle all icmp/fcmp cases.
// TODO: Add CMPM/MM with test coverage.