return Op1;
}
+ unsigned Bitwidth = Op1->getType()->getScalarSizeInBits();
+ APInt DemandedMask = APInt::getAllOnesValue(Bitwidth);
+ APInt KnownZero0 = APInt::getNullValue(Bitwidth);
+ APInt KnownOne0 = APInt::getNullValue(Bitwidth);
+ ComputeMaskedBits(Op0, DemandedMask, KnownZero0, KnownOne0);
+ APInt KnownZero1 = APInt::getNullValue(Bitwidth);
+ APInt KnownOne1 = APInt::getNullValue(Bitwidth);
+ ComputeMaskedBits(Op1, DemandedMask, KnownZero1, KnownOne1);
+
+ if ((KnownZero0 | KnownOne1).isAllOnesValue())
+ return Op0;
+
+ if ((KnownZero1 | KnownOne0).isAllOnesValue())
+ return Op1;
+
// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
MaxRecurse))
#include "llvm/GlobalAlias.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/LLVMContext.h"
+#include "llvm/Metadata.h"
#include "llvm/Operator.h"
#include "llvm/Target/TargetData.h"
+#include "llvm/Support/ConstantRange.h"
#include "llvm/Support/GetElementPtrTypeIterator.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Support/PatternMatch.h"
KnownOne.setBit(BitWidth - 1);
}
+static void computeMaskedBitsLoad(const MDNode &Ranges, const APInt &Mask,
+ APInt &KnownZero) {
+ unsigned BitWidth = Mask.getBitWidth();
+ unsigned NumRanges = Ranges.getNumOperands() / 2;
+ assert(NumRanges >= 1);
+
+ // Use the high end of the ranges to find leading zeros.
+ unsigned MinLeadingZeros = BitWidth;
+ for (unsigned i = 0; i < NumRanges; ++i) {
+ ConstantInt *Lower = cast<ConstantInt>(Ranges.getOperand(2*i + 0));
+ ConstantInt *Upper = cast<ConstantInt>(Ranges.getOperand(2*i + 1));
+ ConstantRange Range(Lower->getValue(), Upper->getValue());
+ if (Range.isWrappedSet())
+ MinLeadingZeros = 0; // -1 has no zeros
+ unsigned LeadingZeros = (Upper->getValue() - 1).countLeadingZeros();
+ MinLeadingZeros = std::min(LeadingZeros, MinLeadingZeros);
+ }
+
+ KnownZero = Mask & APInt::getHighBitsSet(BitWidth, MinLeadingZeros);
+}
/// ComputeMaskedBits - Determine which of the bits specified in Mask are
/// known to be either zero or one and return them in the KnownZero/KnownOne
/// bit sets. This code only analyzes bits in Mask, in order to short-circuit
APInt KnownZero2(KnownZero), KnownOne2(KnownOne);
switch (I->getOpcode()) {
default: break;
+ case Instruction::Load:
+ if (MDNode *MD = cast<LoadInst>(I)->getMetadata(LLVMContext::MD_range))
+ computeMaskedBitsLoad(*MD, Mask, KnownZero);
+ return;
case Instruction::And: {
// If either the LHS or the RHS are Zero, the result is zero.
ComputeMaskedBits(I->getOperand(1), Mask, KnownZero, KnownOne, TD, Depth+1);
--- /dev/null
+; RUN: opt < %s -instsimplify -S | FileCheck %s
+
+define zeroext i1 @_Z3fooPb(i8* nocapture %x) {
+entry:
+ %a = load i8* %x, align 1, !range !0
+ %b = and i8 %a, 1
+ %tobool = icmp ne i8 %b, 0
+ ret i1 %tobool
+}
+
+; CHECK: %a = load i8* %x, align 1, !range !0
+; CHECK-NEXT: %tobool = icmp ne i8 %a, 0
+; CHECK-NEXT: ret i1 %tobool
+
+!0 = metadata !{i8 0, i8 2}