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For PR1205:

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* APIntify commonIntCastTransforms
* APIntify visitTrunc
* APIntify visitZExt

Patch by Zhou Sheng.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35271 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Spencer 2007-03-22 20:56:53 +00:00
parent 0460fb3ea5
commit ad6676e81b
1 changed files with 17 additions and 16 deletions
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33
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -6951,8 +6951,8 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
// See if we can simplify any instructions used by the LHS whose sole
// purpose is to compute bits we don't care about.
uint64_t KnownZero = 0, KnownOne = 0;
if (SimplifyDemandedBits(&CI, cast<IntegerType>(DestTy)->getBitMask(),
APInt KnownZero(DestBitSize, 0), KnownOne(DestBitSize, 0);
if (SimplifyDemandedBits(&CI, APInt::getAllOnesValue(DestBitSize),
KnownZero, KnownOne))
return &CI;
@ -7008,10 +7008,8 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
case Instruction::ZExt: {
// We need to emit an AND to clear the high bits.
assert(SrcBitSize < DestBitSize && "Not a zext?");
Constant *C =
ConstantInt::get(Type::Int64Ty, (1ULL << SrcBitSize)-1);
if (DestBitSize < 64)
C = ConstantExpr::getTrunc(C, DestTy);
Constant *C = ConstantInt::get(APInt::getAllOnesValue(SrcBitSize));
C = ConstantExpr::getZExt(C, DestTy);
return BinaryOperator::createAnd(Res, C);
}
case Instruction::SExt:
@ -7113,7 +7111,7 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
// to an integer, then shift the bit to the appropriate place and then
// cast to integer to avoid the comparison.
if (ConstantInt *Op1C = dyn_cast<ConstantInt>(Op1)) {
uint64_t Op1CV = Op1C->getZExtValue();
APInt Op1CV(Op1C->getValue());
// cast (X == 0) to int --> X^1 iff X has only the low bit set.
// cast (X == 0) to int --> (X>>1)^1 iff X has only the 2nd bit set.
// cast (X == 1) to int --> X iff X has only the low bit set.
@ -7122,10 +7120,11 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
// cast (X != 0) to int --> X>>1 iff X has only the 2nd bit set.
// cast (X != 1) to int --> X^1 iff X has only the low bit set.
// cast (X != 2) to int --> (X>>1)^1 iff X has only the 2nd bit set.
if (Op1CV == 0 || isPowerOf2_64(Op1CV)) {
if (Op1CV == 0 || Op1CV.isPowerOf2()) {
// If Op1C some other power of two, convert:
uint64_t KnownZero, KnownOne;
uint64_t TypeMask = Op1C->getType()->getBitMask();
uint32_t BitWidth = Op1C->getType()->getBitWidth();
APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
APInt TypeMask(APInt::getAllOnesValue(BitWidth));
ComputeMaskedBits(Op0, TypeMask, KnownZero, KnownOne);
// This only works for EQ and NE
@ -7133,9 +7132,9 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
if (pred != ICmpInst::ICMP_NE && pred != ICmpInst::ICMP_EQ)
break;
if (isPowerOf2_64(KnownZero^TypeMask)) { // Exactly 1 possible 1?
if ((KnownZero^TypeMask).isPowerOf2()) { // Exactly 1 possible 1?
bool isNE = pred == ICmpInst::ICMP_NE;
if (Op1CV && (Op1CV != (KnownZero^TypeMask))) {
if (Op1CV != 0 && (Op1CV != (KnownZero^TypeMask))) {
// (X&4) == 2 --> false
// (X&4) != 2 --> true
Constant *Res = ConstantInt::get(Type::Int1Ty, isNE);
@ -7143,7 +7142,7 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
return ReplaceInstUsesWith(CI, Res);
}
unsigned ShiftAmt = Log2_64(KnownZero^TypeMask);
unsigned ShiftAmt = (KnownZero^TypeMask).logBase2();
Value *In = Op0;
if (ShiftAmt) {
// Perform a logical shr by shiftamt.
@ -7179,6 +7178,7 @@ Instruction *InstCombiner::visitTrunc(CastInst &CI) {
Value *Src = CI.getOperand(0);
const Type *Ty = CI.getType();
unsigned DestBitWidth = Ty->getPrimitiveSizeInBits();
unsigned SrcBitWidth = cast<IntegerType>(Src->getType())->getBitWidth();
if (Instruction *SrcI = dyn_cast<Instruction>(Src)) {
switch (SrcI->getOpcode()) {
@ -7190,7 +7190,8 @@ Instruction *InstCombiner::visitTrunc(CastInst &CI) {
unsigned ShAmt = ShAmtV->getZExtValue();
// Get a mask for the bits shifting in.
uint64_t Mask = (~0ULL >> (64-ShAmt)) << DestBitWidth;
APInt Mask(APInt::getAllOnesValue(SrcBitWidth).lshr(
SrcBitWidth-ShAmt).shl(DestBitWidth));
Value* SrcIOp0 = SrcI->getOperand(0);
if (SrcI->hasOneUse() && MaskedValueIsZero(SrcIOp0, Mask)) {
if (ShAmt >= DestBitWidth) // All zeros.
@ -7249,8 +7250,8 @@ Instruction *InstCombiner::visitZExt(CastInst &CI) {
// If we're actually extending zero bits and the trunc is a no-op
if (MidSize < DstSize && SrcSize == DstSize) {
// Replace both of the casts with an And of the type mask.
uint64_t AndValue = cast<IntegerType>(CSrc->getType())->getBitMask();
Constant *AndConst = ConstantInt::get(A->getType(), AndValue);
APInt AndValue(APInt::getAllOnesValue(MidSize).zext(SrcSize));
Constant *AndConst = ConstantInt::get(AndValue);
Instruction *And =
BinaryOperator::createAnd(CSrc->getOperand(0), AndConst);
// Unfortunately, if the type changed, we need to cast it back.