Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.581 -> 1.582
---
Log message:
eliminate some uses of canLosslesslyBitCastTo, this actually makes the code
stronger, by nuking
relational pointer comparisons with casts.
---
Diffs of the changes: (+14 -15)
InstructionCombining.cpp | 29 ++++++++++++++---------------
1 files changed, 14 insertions(+), 15 deletions(-)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.581
llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.582
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.581 Fri Jan 5
01:36:08 2007
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Fri Jan 5 19:45:59 2007
@@ -5133,25 +5133,22 @@
return NI;
// Test to see if the operands of the icmp are casted versions of other
- // values. If the cast can be stripped off both arguments, we do so now.
- if (CastInst *CI = dyn_cast<CastInst>(Op0)) {
- Value *CastOp0 = CI->getOperand(0);
- if (CI->isLosslessCast() && I.isEquality() &&
- (isa<Constant>(Op1) || isa<CastInst>(Op1))) {
+ // values. If the ptr->ptr cast can be stripped off both arguments, we do so
+ // now.
+ if (BitCastInst *CI = dyn_cast<BitCastInst>(Op0)) {
+ if (isa<PointerType>(Op0->getType()) &&
+ (isa<Constant>(Op1) || isa<BitCastInst>(Op1))) {
// We keep moving the cast from the left operand over to the right
// operand, where it can often be eliminated completely.
- Op0 = CastOp0;
+ Op0 = CI->getOperand(0);
- // If operand #1 is a cast instruction, see if we can eliminate it as
- // well.
- if (CastInst *CI2 = dyn_cast<CastInst>(Op1)) {
- Value *CI2Op0 = CI2->getOperand(0);
- if (CI2Op0->getType()->canLosslesslyBitCastTo(Op0->getType()))
- Op1 = CI2Op0;
- }
+ // If operand #1 is a bitcast instruction, it must also be a ptr->ptr
cast
+ // so eliminate it as well.
+ if (BitCastInst *CI2 = dyn_cast<BitCastInst>(Op1))
+ Op1 = CI2->getOperand(0);
// If Op1 is a constant, we can fold the cast into the constant.
- if (Op1->getType() != Op0->getType())
+ if (Op0->getType() != Op1->getType())
if (Constant *Op1C = dyn_cast<Constant>(Op1)) {
Op1 = ConstantExpr::getBitCast(Op1C, Op0->getType());
} else {
@@ -5160,7 +5157,9 @@
}
return new ICmpInst(I.getPredicate(), Op0, Op1);
}
-
+ }
+
+ if (isa<CastInst>(Op0)) {
// Handle the special case of: icmp (cast bool to X), <cst>
// This comes up when you have code like
// int X = A < B;
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