[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
Chris Lattner
lattner at cs.uiuc.edu
Wed Jul 23 12:58:02 PDT 2003
Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.100 -> 1.101
---
Log message:
IC: (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
Minor code cleanup
---
Diffs of the changes:
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.100 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.101
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.100 Wed Jul 23 12:26:36 2003
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Wed Jul 23 12:57:01 2003
@@ -493,19 +493,31 @@
return ReplaceInstUsesWith(I, Op1);
// and X, -1 == X
- if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1))
+ if (ConstantIntegral *RHS = dyn_cast<ConstantIntegral>(Op1)) {
if (RHS->isAllOnesValue())
return ReplaceInstUsesWith(I, Op0);
+ // (X ^ C1) & C2 --> (X & C2) ^ (C1&C2)
+ if (Instruction *Op0I = dyn_cast<Instruction>(Op0))
+ if (Op0I->getOpcode() == Instruction::Xor && isOnlyUse(Op0))
+ if (ConstantInt *Op0CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) {
+ std::string Op0Name = Op0I->getName(); Op0I->setName("");
+ Instruction *And = BinaryOperator::create(Instruction::And,
+ Op0I->getOperand(0), RHS,
+ Op0Name);
+ InsertNewInstBefore(And, I);
+ return BinaryOperator::create(Instruction::Xor, And, *RHS & *Op0CI);
+ }
+ }
+
Value *Op0NotVal = dyn_castNotVal(Op0);
Value *Op1NotVal = dyn_castNotVal(Op1);
// (~A & ~B) == (~(A | B)) - Demorgan's Law
if (Op0NotVal && Op1NotVal && isOnlyUse(Op0) && isOnlyUse(Op1)) {
Instruction *Or = BinaryOperator::create(Instruction::Or, Op0NotVal,
- Op1NotVal,I.getName()+".demorgan",
- &I);
- WorkList.push_back(Or);
+ Op1NotVal,I.getName()+".demorgan");
+ InsertNewInstBefore(Or, I);
return BinaryOperator::createNot(Or);
}
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