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simplify some code 

llvm-svn: 34914
This commit is contained in:
Chris Lattner 2007-03-04 23:16:36 +00:00
parent 47206667c0
commit ab2f913b68
1 changed files with 17 additions and 18 deletions
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35
llvm/lib/Transforms/Scalar/InstructionCombining.cpp
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@ -850,6 +850,7 @@ static void ComputeUnsignedMinMaxValuesFromKnownBits(const Type *Ty,
bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask, bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
uint64_t &KnownZero, uint64_t &KnownOne, uint64_t &KnownZero, uint64_t &KnownOne,
unsigned Depth) { unsigned Depth) {
const IntegerType *VTy = cast<IntegerType>(V->getType());
if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) { if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
// We know all of the bits for a constant! // We know all of the bits for a constant!
KnownOne = CI->getZExtValue() & DemandedMask; KnownOne = CI->getZExtValue() & DemandedMask;
@ -866,10 +867,10 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
} }
// If this is the root being simplified, allow it to have multiple uses, // If this is the root being simplified, allow it to have multiple uses,
// just set the DemandedMask to all bits. // just set the DemandedMask to all bits.
DemandedMask = cast<IntegerType>(V->getType())->getBitMask(); DemandedMask = VTy->getBitMask();
} else if (DemandedMask == 0) { // Not demanding any bits from V. } else if (DemandedMask == 0) { // Not demanding any bits from V.
if (V != UndefValue::get(V->getType())) if (V != UndefValue::get(VTy))
return UpdateValueUsesWith(V, UndefValue::get(V->getType())); return UpdateValueUsesWith(V, UndefValue::get(VTy));
return false; return false;
} else if (Depth == 6) { // Limit search depth. } else if (Depth == 6) { // Limit search depth.
return false; return false;
@ -878,7 +879,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
Instruction *I = dyn_cast<Instruction>(V); Instruction *I = dyn_cast<Instruction>(V);
if (!I) return false; // Only analyze instructions. if (!I) return false; // Only analyze instructions.
DemandedMask &= cast<IntegerType>(V->getType())->getBitMask(); DemandedMask &= VTy->getBitMask();
uint64_t KnownZero2 = 0, KnownOne2 = 0; uint64_t KnownZero2 = 0, KnownOne2 = 0;
switch (I->getOpcode()) { switch (I->getOpcode()) {
@ -906,7 +907,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// If all of the demanded bits in the inputs are known zeros, return zero. // If all of the demanded bits in the inputs are known zeros, return zero.
if ((DemandedMask & (KnownZero|KnownZero2)) == DemandedMask) if ((DemandedMask & (KnownZero|KnownZero2)) == DemandedMask)
return UpdateValueUsesWith(I, Constant::getNullValue(I->getType())); return UpdateValueUsesWith(I, Constant::getNullValue(VTy));
// If the RHS is a constant, see if we can simplify it. // If the RHS is a constant, see if we can simplify it.
if (ShrinkDemandedConstant(I, 1, DemandedMask & ~KnownZero2)) if (ShrinkDemandedConstant(I, 1, DemandedMask & ~KnownZero2))
@ -991,8 +992,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2 // e.g. (X | C1) ^ C2 --> (X | C1) & ~C2 iff (C1&C2) == C2
if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask) { // all known if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask) { // all known
if ((KnownOne & KnownOne2) == KnownOne) { if ((KnownOne & KnownOne2) == KnownOne) {
Constant *AndC = ConstantInt::get(I->getType(), Constant *AndC = ConstantInt::get(VTy, ~KnownOne & DemandedMask);
~KnownOne & DemandedMask);
Instruction *And = Instruction *And =
BinaryOperator::createAnd(I->getOperand(0), AndC, "tmp"); BinaryOperator::createAnd(I->getOperand(0), AndC, "tmp");
InsertNewInstBefore(And, *I); InsertNewInstBefore(And, *I);
@ -1048,7 +1048,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// Compute the bits in the result that are not present in the input. // Compute the bits in the result that are not present in the input.
const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType()); const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType());
uint64_t NotIn = ~SrcTy->getBitMask(); uint64_t NotIn = ~SrcTy->getBitMask();
uint64_t NewBits = cast<IntegerType>(I->getType())->getBitMask() & NotIn; uint64_t NewBits = VTy->getBitMask() & NotIn;
DemandedMask &= SrcTy->getBitMask(); DemandedMask &= SrcTy->getBitMask();
if (SimplifyDemandedBits(I->getOperand(0), DemandedMask, if (SimplifyDemandedBits(I->getOperand(0), DemandedMask,
@ -1063,7 +1063,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// Compute the bits in the result that are not present in the input. // Compute the bits in the result that are not present in the input.
const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType()); const IntegerType *SrcTy = cast<IntegerType>(I->getOperand(0)->getType());
uint64_t NotIn = ~SrcTy->getBitMask(); uint64_t NotIn = ~SrcTy->getBitMask();
uint64_t NewBits = cast<IntegerType>(I->getType())->getBitMask() & NotIn; uint64_t NewBits = VTy->getBitMask() & NotIn;
// Get the sign bit for the source type // Get the sign bit for the source type
uint64_t InSignBit = 1ULL << (SrcTy->getPrimitiveSizeInBits()-1); uint64_t InSignBit = 1ULL << (SrcTy->getPrimitiveSizeInBits()-1);
@ -1086,8 +1086,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// convert this into a zero extension. // convert this into a zero extension.
if ((KnownZero & InSignBit) || (NewBits & ~DemandedMask) == NewBits) { if ((KnownZero & InSignBit) || (NewBits & ~DemandedMask) == NewBits) {
// Convert to ZExt cast // Convert to ZExt cast
CastInst *NewCast = CastInst::create( CastInst *NewCast = new ZExtInst(I->getOperand(0), VTy, I->getName(), I);
Instruction::ZExt, I->getOperand(0), I->getType(), I->getName(), I);
return UpdateValueUsesWith(I, NewCast); return UpdateValueUsesWith(I, NewCast);
} else if (KnownOne & InSignBit) { // Input sign bit known set } else if (KnownOne & InSignBit) { // Input sign bit known set
KnownOne |= NewBits; KnownOne |= NewBits;
@ -1112,7 +1111,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// either. // either.
// Shift the demanded mask up so that it's at the top of the uint64_t. // Shift the demanded mask up so that it's at the top of the uint64_t.
unsigned BitWidth = I->getType()->getPrimitiveSizeInBits(); unsigned BitWidth = VTy->getPrimitiveSizeInBits();
unsigned NLZ = CountLeadingZeros_64(DemandedMask << (64-BitWidth)); unsigned NLZ = CountLeadingZeros_64(DemandedMask << (64-BitWidth));
// If the top bit of the output is demanded, demand everything from the // If the top bit of the output is demanded, demand everything from the
@ -1208,8 +1207,8 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// Compute the new bits that are at the top now. // Compute the new bits that are at the top now.
uint64_t HighBits = (1ULL << ShiftAmt)-1; uint64_t HighBits = (1ULL << ShiftAmt)-1;
HighBits <<= I->getType()->getPrimitiveSizeInBits() - ShiftAmt; HighBits <<= VTy->getBitWidth() - ShiftAmt;
uint64_t TypeMask = cast<IntegerType>(I->getType())->getBitMask(); uint64_t TypeMask = VTy->getBitMask();
// Unsigned shift right. // Unsigned shift right.
if (SimplifyDemandedBits(I->getOperand(0), if (SimplifyDemandedBits(I->getOperand(0),
(DemandedMask << ShiftAmt) & TypeMask, (DemandedMask << ShiftAmt) & TypeMask,
@ -1241,8 +1240,8 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// Compute the new bits that are at the top now. // Compute the new bits that are at the top now.
uint64_t HighBits = (1ULL << ShiftAmt)-1; uint64_t HighBits = (1ULL << ShiftAmt)-1;
HighBits <<= I->getType()->getPrimitiveSizeInBits() - ShiftAmt; HighBits <<= VTy->getBitWidth() - ShiftAmt;
uint64_t TypeMask = cast<IntegerType>(I->getType())->getBitMask(); uint64_t TypeMask = VTy->getBitMask();
// Signed shift right. // Signed shift right.
if (SimplifyDemandedBits(I->getOperand(0), if (SimplifyDemandedBits(I->getOperand(0),
(DemandedMask << ShiftAmt) & TypeMask, (DemandedMask << ShiftAmt) & TypeMask,
@ -1255,7 +1254,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
KnownOne >>= ShiftAmt; KnownOne >>= ShiftAmt;
// Handle the sign bits. // Handle the sign bits.
uint64_t SignBit = 1ULL << (I->getType()->getPrimitiveSizeInBits()-1); uint64_t SignBit = 1ULL << (VTy->getBitWidth()-1);
SignBit >>= ShiftAmt; // Adjust to where it is now in the mask. SignBit >>= ShiftAmt; // Adjust to where it is now in the mask.
// If the input sign bit is known to be zero, or if none of the top bits // If the input sign bit is known to be zero, or if none of the top bits
@ -1276,7 +1275,7 @@ bool InstCombiner::SimplifyDemandedBits(Value *V, uint64_t DemandedMask,
// If the client is only demanding bits that we know, return the known // If the client is only demanding bits that we know, return the known
// constant. // constant.
if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask) if ((DemandedMask & (KnownZero|KnownOne)) == DemandedMask)
return UpdateValueUsesWith(I, ConstantInt::get(I->getType(), KnownOne)); return UpdateValueUsesWith(I, ConstantInt::get(VTy, KnownOne));
return false; return false;
} }