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path: root/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
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Diffstat (limited to 'lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp')
-rw-r--r--lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp92
1 files changed, 38 insertions, 54 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
index 4028a92771a4..5df55f01b83f 100644
--- a/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp
@@ -158,8 +158,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
SimplifyDemandedBits(I, 0, DemandedMask & ~RHSKnown.Zero, LHSKnown,
Depth + 1))
return I;
- assert(!(RHSKnown.Zero & RHSKnown.One) && "Bits known to be one AND zero?");
- assert(!(LHSKnown.Zero & LHSKnown.One) && "Bits known to be one AND zero?");
+ assert(!RHSKnown.hasConflict() && "Bits known to be one AND zero?");
+ assert(!LHSKnown.hasConflict() && "Bits known to be one AND zero?");
// Output known-0 are known to be clear if zero in either the LHS | RHS.
APInt IKnownZero = RHSKnown.Zero | LHSKnown.Zero;
@@ -192,8 +192,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
SimplifyDemandedBits(I, 0, DemandedMask & ~RHSKnown.One, LHSKnown,
Depth + 1))
return I;
- assert(!(RHSKnown.Zero & RHSKnown.One) && "Bits known to be one AND zero?");
- assert(!(LHSKnown.Zero & LHSKnown.One) && "Bits known to be one AND zero?");
+ assert(!RHSKnown.hasConflict() && "Bits known to be one AND zero?");
+ assert(!LHSKnown.hasConflict() && "Bits known to be one AND zero?");
// Output known-0 bits are only known if clear in both the LHS & RHS.
APInt IKnownZero = RHSKnown.Zero & LHSKnown.Zero;
@@ -224,8 +224,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (SimplifyDemandedBits(I, 1, DemandedMask, RHSKnown, Depth + 1) ||
SimplifyDemandedBits(I, 0, DemandedMask, LHSKnown, Depth + 1))
return I;
- assert(!(RHSKnown.Zero & RHSKnown.One) && "Bits known to be one AND zero?");
- assert(!(LHSKnown.Zero & LHSKnown.One) && "Bits known to be one AND zero?");
+ assert(!RHSKnown.hasConflict() && "Bits known to be one AND zero?");
+ assert(!LHSKnown.hasConflict() && "Bits known to be one AND zero?");
// Output known-0 bits are known if clear or set in both the LHS & RHS.
APInt IKnownZero = (RHSKnown.Zero & LHSKnown.Zero) |
@@ -313,8 +313,8 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (SimplifyDemandedBits(I, 2, DemandedMask, RHSKnown, Depth + 1) ||
SimplifyDemandedBits(I, 1, DemandedMask, LHSKnown, Depth + 1))
return I;
- assert(!(RHSKnown.Zero & RHSKnown.One) && "Bits known to be one AND zero?");
- assert(!(LHSKnown.Zero & LHSKnown.One) && "Bits known to be one AND zero?");
+ assert(!RHSKnown.hasConflict() && "Bits known to be one AND zero?");
+ assert(!LHSKnown.hasConflict() && "Bits known to be one AND zero?");
// If the operands are constants, see if we can simplify them.
if (ShrinkDemandedConstant(I, 1, DemandedMask) ||
@@ -325,15 +325,19 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
Known.One = RHSKnown.One & LHSKnown.One;
Known.Zero = RHSKnown.Zero & LHSKnown.Zero;
break;
+ case Instruction::ZExt:
case Instruction::Trunc: {
- unsigned truncBf = I->getOperand(0)->getType()->getScalarSizeInBits();
- DemandedMask = DemandedMask.zext(truncBf);
- Known = Known.zext(truncBf);
- if (SimplifyDemandedBits(I, 0, DemandedMask, Known, Depth + 1))
+ unsigned SrcBitWidth = I->getOperand(0)->getType()->getScalarSizeInBits();
+
+ APInt InputDemandedMask = DemandedMask.zextOrTrunc(SrcBitWidth);
+ KnownBits InputKnown(SrcBitWidth);
+ if (SimplifyDemandedBits(I, 0, InputDemandedMask, InputKnown, Depth + 1))
return I;
- DemandedMask = DemandedMask.trunc(BitWidth);
- Known = Known.trunc(BitWidth);
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
+ Known = Known.zextOrTrunc(BitWidth);
+ // Any top bits are known to be zero.
+ if (BitWidth > SrcBitWidth)
+ Known.Zero.setBitsFrom(SrcBitWidth);
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
break;
}
case Instruction::BitCast:
@@ -355,56 +359,36 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (SimplifyDemandedBits(I, 0, DemandedMask, Known, Depth + 1))
return I;
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
- break;
- case Instruction::ZExt: {
- // Compute the bits in the result that are not present in the input.
- unsigned SrcBitWidth =I->getOperand(0)->getType()->getScalarSizeInBits();
-
- DemandedMask = DemandedMask.trunc(SrcBitWidth);
- Known = Known.trunc(SrcBitWidth);
- if (SimplifyDemandedBits(I, 0, DemandedMask, Known, Depth + 1))
- return I;
- DemandedMask = DemandedMask.zext(BitWidth);
- Known = Known.zext(BitWidth);
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
- // The top bits are known to be zero.
- Known.Zero.setBitsFrom(SrcBitWidth);
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
break;
- }
case Instruction::SExt: {
// Compute the bits in the result that are not present in the input.
- unsigned SrcBitWidth =I->getOperand(0)->getType()->getScalarSizeInBits();
+ unsigned SrcBitWidth = I->getOperand(0)->getType()->getScalarSizeInBits();
- APInt InputDemandedBits = DemandedMask &
- APInt::getLowBitsSet(BitWidth, SrcBitWidth);
+ APInt InputDemandedBits = DemandedMask.trunc(SrcBitWidth);
- APInt NewBits(APInt::getBitsSetFrom(BitWidth, SrcBitWidth));
// If any of the sign extended bits are demanded, we know that the sign
// bit is demanded.
- if ((NewBits & DemandedMask) != 0)
+ if (DemandedMask.getActiveBits() > SrcBitWidth)
InputDemandedBits.setBit(SrcBitWidth-1);
- InputDemandedBits = InputDemandedBits.trunc(SrcBitWidth);
- Known = Known.trunc(SrcBitWidth);
- if (SimplifyDemandedBits(I, 0, InputDemandedBits, Known, Depth + 1))
+ KnownBits InputKnown(SrcBitWidth);
+ if (SimplifyDemandedBits(I, 0, InputDemandedBits, InputKnown, Depth + 1))
return I;
- InputDemandedBits = InputDemandedBits.zext(BitWidth);
- Known = Known.zext(BitWidth);
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
-
- // If the sign bit of the input is known set or clear, then we know the
- // top bits of the result.
// If the input sign bit is known zero, or if the NewBits are not demanded
// convert this into a zero extension.
- if (Known.Zero[SrcBitWidth-1] || (NewBits & ~DemandedMask) == NewBits) {
- // Convert to ZExt cast
+ if (InputKnown.isNonNegative() ||
+ DemandedMask.getActiveBits() <= SrcBitWidth) {
+ // Convert to ZExt cast.
CastInst *NewCast = new ZExtInst(I->getOperand(0), VTy, I->getName());
return InsertNewInstWith(NewCast, *I);
- } else if (Known.One[SrcBitWidth-1]) { // Input sign bit known set
- Known.One |= NewBits;
- }
+ }
+
+ // If the sign bit of the input is known set or clear, then we know the
+ // top bits of the result.
+ Known = InputKnown.sext(BitWidth);
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
break;
}
case Instruction::Add:
@@ -467,7 +451,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (SimplifyDemandedBits(I, 0, DemandedMaskIn, Known, Depth + 1))
return I;
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero <<= ShiftAmt;
Known.One <<= ShiftAmt;
// low bits known zero.
@@ -491,7 +475,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (SimplifyDemandedBits(I, 0, DemandedMaskIn, Known, Depth + 1))
return I;
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
Known.Zero.lshrInPlace(ShiftAmt);
Known.One.lshrInPlace(ShiftAmt);
if (ShiftAmt)
@@ -535,7 +519,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (SimplifyDemandedBits(I, 0, DemandedMaskIn, Known, Depth + 1))
return I;
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
// Compute the new bits that are at the top now.
APInt HighBits(APInt::getHighBitsSet(BitWidth, ShiftAmt));
Known.Zero.lshrInPlace(ShiftAmt);
@@ -590,7 +574,7 @@ Value *InstCombiner::SimplifyDemandedUseBits(Value *V, APInt DemandedMask,
if (LHSKnown.isNegative() && LowBits.intersects(LHSKnown.One))
Known.One |= ~LowBits;
- assert(!(Known.Zero & Known.One) && "Bits known to be one AND zero?");
+ assert(!Known.hasConflict() && "Bits known to be one AND zero?");
break;
}
}
generated by cgit v1.2.3 (git 2.25.1) at 2025-07-25 16:59:01 +0000