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-rw-r--r--lib/Transforms/Scalar/InstructionCombining.cpp225
1 files changed, 129 insertions, 96 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 083dd52..8ebd2cc 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -236,6 +236,8 @@ namespace {
Instruction *visitCallSite(CallSite CS);
bool transformConstExprCastCall(CallSite CS);
Instruction *transformCallThroughTrampoline(CallSite CS);
+ Instruction *transformZExtICmp(ICmpInst *ICI, Instruction &CI,
+ bool DoXform = true);
public:
// InsertNewInstBefore - insert an instruction New before instruction Old
@@ -4363,18 +4365,22 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
if (CastInst *Op0C = dyn_cast<CastInst>(Op0)) {
if (CastInst *Op1C = dyn_cast<CastInst>(Op1))
if (Op0C->getOpcode() == Op1C->getOpcode()) {// same cast kind ?
- const Type *SrcTy = Op0C->getOperand(0)->getType();
- if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isInteger() &&
- // Only do this if the casts both really cause code to be generated.
- ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0),
- I.getType(), TD) &&
- ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0),
- I.getType(), TD)) {
- Instruction *NewOp = BinaryOperator::createOr(Op0C->getOperand(0),
- Op1C->getOperand(0),
- I.getName());
- InsertNewInstBefore(NewOp, I);
- return CastInst::create(Op0C->getOpcode(), NewOp, I.getType());
+ if (!isa<ICmpInst>(Op0C->getOperand(0)) ||
+ !isa<ICmpInst>(Op1C->getOperand(0))) {
+ const Type *SrcTy = Op0C->getOperand(0)->getType();
+ if (SrcTy == Op1C->getOperand(0)->getType() && SrcTy->isInteger() &&
+ // Only do this if the casts both really cause code to be
+ // generated.
+ ValueRequiresCast(Op0C->getOpcode(), Op0C->getOperand(0),
+ I.getType(), TD) &&
+ ValueRequiresCast(Op1C->getOpcode(), Op1C->getOperand(0),
+ I.getType(), TD)) {
+ Instruction *NewOp = BinaryOperator::createOr(Op0C->getOperand(0),
+ Op1C->getOperand(0),
+ I.getName());
+ InsertNewInstBefore(NewOp, I);
+ return CastInst::create(Op0C->getOpcode(), NewOp, I.getType());
+ }
}
}
}
@@ -7188,6 +7194,101 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
return 0;
}
+/// transformZExtICmp - Transform (zext icmp) to bitwise / integer operations
+/// in order to eliminate the icmp.
+Instruction *InstCombiner::transformZExtICmp(ICmpInst *ICI, Instruction &CI,
+ bool DoXform) {
+ // If we are just checking for a icmp eq of a single bit and zext'ing it
+ // 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>(ICI->getOperand(1))) {
+ const APInt &Op1CV = Op1C->getValue();
+
+ // zext (x <s 0) to i32 --> x>>u31 true if signbit set.
+ // zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
+ if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV == 0) ||
+ (ICI->getPredicate() == ICmpInst::ICMP_SGT &&Op1CV.isAllOnesValue())) {
+ if (!DoXform) return ICI;
+
+ Value *In = ICI->getOperand(0);
+ Value *Sh = ConstantInt::get(In->getType(),
+ In->getType()->getPrimitiveSizeInBits()-1);
+ In = InsertNewInstBefore(BinaryOperator::createLShr(In, Sh,
+ In->getName()+".lobit"),
+ CI);
+ if (In->getType() != CI.getType())
+ In = CastInst::createIntegerCast(In, CI.getType(),
+ false/*ZExt*/, "tmp", &CI);
+
+ if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
+ Constant *One = ConstantInt::get(In->getType(), 1);
+ In = InsertNewInstBefore(BinaryOperator::createXor(In, One,
+ In->getName()+".not"),
+ CI);
+ }
+
+ return ReplaceInstUsesWith(CI, In);
+ }
+
+
+
+ // zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
+ // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
+ // zext (X == 1) to i32 --> X iff X has only the low bit set.
+ // zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
+ // zext (X != 0) to i32 --> X iff X has only the low bit set.
+ // zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
+ // zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
+ // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
+ if ((Op1CV == 0 || Op1CV.isPowerOf2()) &&
+ // This only works for EQ and NE
+ ICI->isEquality()) {
+ // If Op1C some other power of two, convert:
+ uint32_t BitWidth = Op1C->getType()->getBitWidth();
+ APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
+ APInt TypeMask(APInt::getAllOnesValue(BitWidth));
+ ComputeMaskedBits(ICI->getOperand(0), TypeMask, KnownZero, KnownOne);
+
+ APInt KnownZeroMask(~KnownZero);
+ if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
+ if (!DoXform) return ICI;
+
+ bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
+ if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
+ // (X&4) == 2 --> false
+ // (X&4) != 2 --> true
+ Constant *Res = ConstantInt::get(Type::Int1Ty, isNE);
+ Res = ConstantExpr::getZExt(Res, CI.getType());
+ return ReplaceInstUsesWith(CI, Res);
+ }
+
+ uint32_t ShiftAmt = KnownZeroMask.logBase2();
+ Value *In = ICI->getOperand(0);
+ if (ShiftAmt) {
+ // Perform a logical shr by shiftamt.
+ // Insert the shift to put the result in the low bit.
+ In = InsertNewInstBefore(BinaryOperator::createLShr(In,
+ ConstantInt::get(In->getType(), ShiftAmt),
+ In->getName()+".lobit"), CI);
+ }
+
+ if ((Op1CV != 0) == isNE) { // Toggle the low bit.
+ Constant *One = ConstantInt::get(In->getType(), 1);
+ In = BinaryOperator::createXor(In, One, "tmp");
+ InsertNewInstBefore(cast<Instruction>(In), CI);
+ }
+
+ if (CI.getType() == In->getType())
+ return ReplaceInstUsesWith(CI, In);
+ else
+ return CastInst::createIntegerCast(In, CI.getType(), false/*ZExt*/);
+ }
+ }
+ }
+
+ return 0;
+}
+
Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
// If one of the common conversion will work ..
if (Instruction *Result = commonIntCastTransforms(CI))
@@ -7224,92 +7325,24 @@ Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
}
}
- if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src)) {
- // If we are just checking for a icmp eq of a single bit and zext'ing it
- // 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>(ICI->getOperand(1))) {
- const APInt &Op1CV = Op1C->getValue();
-
- // zext (x <s 0) to i32 --> x>>u31 true if signbit set.
- // zext (x >s -1) to i32 --> (x>>u31)^1 true if signbit clear.
- if ((ICI->getPredicate() == ICmpInst::ICMP_SLT && Op1CV == 0) ||
- (ICI->getPredicate() == ICmpInst::ICMP_SGT &&Op1CV.isAllOnesValue())){
- Value *In = ICI->getOperand(0);
- Value *Sh = ConstantInt::get(In->getType(),
- In->getType()->getPrimitiveSizeInBits()-1);
- In = InsertNewInstBefore(BinaryOperator::createLShr(In, Sh,
- In->getName()+".lobit"),
- CI);
- if (In->getType() != CI.getType())
- In = CastInst::createIntegerCast(In, CI.getType(),
- false/*ZExt*/, "tmp", &CI);
+ if (ICmpInst *ICI = dyn_cast<ICmpInst>(Src))
+ return transformZExtICmp(ICI, CI);
- if (ICI->getPredicate() == ICmpInst::ICMP_SGT) {
- Constant *One = ConstantInt::get(In->getType(), 1);
- In = InsertNewInstBefore(BinaryOperator::createXor(In, One,
- In->getName()+".not"),
- CI);
- }
-
- return ReplaceInstUsesWith(CI, In);
- }
-
-
-
- // zext (X == 0) to i32 --> X^1 iff X has only the low bit set.
- // zext (X == 0) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
- // zext (X == 1) to i32 --> X iff X has only the low bit set.
- // zext (X == 2) to i32 --> X>>1 iff X has only the 2nd bit set.
- // zext (X != 0) to i32 --> X iff X has only the low bit set.
- // zext (X != 0) to i32 --> X>>1 iff X has only the 2nd bit set.
- // zext (X != 1) to i32 --> X^1 iff X has only the low bit set.
- // zext (X != 2) to i32 --> (X>>1)^1 iff X has only the 2nd bit set.
- if ((Op1CV == 0 || Op1CV.isPowerOf2()) &&
- // This only works for EQ and NE
- ICI->isEquality()) {
- // If Op1C some other power of two, convert:
- uint32_t BitWidth = Op1C->getType()->getBitWidth();
- APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
- APInt TypeMask(APInt::getAllOnesValue(BitWidth));
- ComputeMaskedBits(ICI->getOperand(0), TypeMask, KnownZero, KnownOne);
-
- APInt KnownZeroMask(~KnownZero);
- if (KnownZeroMask.isPowerOf2()) { // Exactly 1 possible 1?
- bool isNE = ICI->getPredicate() == ICmpInst::ICMP_NE;
- if (Op1CV != 0 && (Op1CV != KnownZeroMask)) {
- // (X&4) == 2 --> false
- // (X&4) != 2 --> true
- Constant *Res = ConstantInt::get(Type::Int1Ty, isNE);
- Res = ConstantExpr::getZExt(Res, CI.getType());
- return ReplaceInstUsesWith(CI, Res);
- }
-
- uint32_t ShiftAmt = KnownZeroMask.logBase2();
- Value *In = ICI->getOperand(0);
- if (ShiftAmt) {
- // Perform a logical shr by shiftamt.
- // Insert the shift to put the result in the low bit.
- In = InsertNewInstBefore(
- BinaryOperator::createLShr(In,
- ConstantInt::get(In->getType(), ShiftAmt),
- In->getName()+".lobit"), CI);
- }
-
- if ((Op1CV != 0) == isNE) { // Toggle the low bit.
- Constant *One = ConstantInt::get(In->getType(), 1);
- In = BinaryOperator::createXor(In, One, "tmp");
- InsertNewInstBefore(cast<Instruction>(In), CI);
- }
-
- if (CI.getType() == In->getType())
- return ReplaceInstUsesWith(CI, In);
- else
- return CastInst::createIntegerCast(In, CI.getType(), false/*ZExt*/);
- }
- }
+ BinaryOperator *SrcI = dyn_cast<BinaryOperator>(Src);
+ if (SrcI && SrcI->getOpcode() == Instruction::Or) {
+ // zext (or icmp, icmp) --> or (zext icmp), (zext icmp) if at least one
+ // of the (zext icmp) will be transformed.
+ ICmpInst *LHS = dyn_cast<ICmpInst>(SrcI->getOperand(0));
+ ICmpInst *RHS = dyn_cast<ICmpInst>(SrcI->getOperand(1));
+ if (LHS && RHS && LHS->hasOneUse() && RHS->hasOneUse() &&
+ (transformZExtICmp(LHS, CI, false) ||
+ transformZExtICmp(RHS, CI, false))) {
+ Value *LCast = InsertCastBefore(Instruction::ZExt, LHS, CI.getType(), CI);
+ Value *RCast = InsertCastBefore(Instruction::ZExt, RHS, CI.getType(), CI);
+ return BinaryOperator::create(Instruction::Or, LCast, RCast);
}
- }
+ }
+
return 0;
}
generated by cgit v1.1 at 2025-10-31 06:44:03 +0000