[ValueTracking][SelectionDAG] Use KnownBits::reverseBits/byteSwap. NFC #155847
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@llvm/pr-subscribers-llvm-analysis @llvm/pr-subscribers-llvm-selectiondag Author: Craig Topper (topperc) ChangesFull diff: https://github.com/llvm/llvm-project/pull/155847.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 7fe129b8456f6..e6282fc8cdbbc 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1834,13 +1834,11 @@ static void computeKnownBitsFromOperator(const Operator *I,
}
case Intrinsic::bitreverse:
computeKnownBits(I->getOperand(0), DemandedElts, Known2, Q, Depth + 1);
- Known.Zero |= Known2.Zero.reverseBits();
- Known.One |= Known2.One.reverseBits();
+ Known = Known.unionWith(Known2.reverseBits());
break;
case Intrinsic::bswap:
computeKnownBits(I->getOperand(0), DemandedElts, Known2, Q, Depth + 1);
- Known.Zero |= Known2.Zero.byteSwap();
- Known.One |= Known2.One.byteSwap();
+ Known = Known.unionWith(Known2.byteSwap());
break;
case Intrinsic::ctlz: {
computeKnownBits(I->getOperand(0), DemandedElts, Known2, Q, Depth + 1);
diff --git a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index 402a012e8e555..7e5844d1a8963 100644
--- a/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -2363,8 +2363,7 @@ bool TargetLowering::SimplifyDemandedBits(
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedElts, Known2, TLO,
Depth + 1))
return true;
- Known.One = Known2.One.reverseBits();
- Known.Zero = Known2.Zero.reverseBits();
+ Known = Known2.reverseBits();
break;
}
case ISD::BSWAP: {
@@ -2397,8 +2396,7 @@ bool TargetLowering::SimplifyDemandedBits(
if (SimplifyDemandedBits(Src, DemandedSrcBits, DemandedElts, Known2, TLO,
Depth + 1))
return true;
- Known.One = Known2.One.byteSwap();
- Known.Zero = Known2.Zero.byteSwap();
+ Known = Known2.byteSwap();
break;
}
case ISD::CTPOP: {
|
RKSimon
reviewed
Aug 28, 2025
| @@ -1834,13 +1834,11 @@ static void computeKnownBitsFromOperator(const Operator *I, | |||
| } | |||
| case Intrinsic::bitreverse: | |||
| computeKnownBits(I->getOperand(0), DemandedElts, Known2, Q, Depth + 1); | |||
| Known.Zero |= Known2.Zero.reverseBits(); | |||
| Known.One |= Known2.One.reverseBits(); | |||
| Known = Known.unionWith(Known2.reverseBits()); | |||
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why isn't this Known = Known2.reverseBits()?
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or why isn't the abs case Known = Known.unionWith(Known2.abs(IntMinIsPoison));?
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I guess they should all use unionWith, to take advantage of any ConstantRange info that might have been calculated before this switch.
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bitreverse and bswap started doing the union here ad5c2d0. abs was added later.
RKSimon
approved these changes
Aug 28, 2025
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