Changes in directory llvm/lib/Transforms/Scalar:
InstructionCombining.cpp updated: 1.438 -> 1.439
---
Log message:
Fold (X|C1)^C2 -> X^(C1|C2) when possible. This implements
InstCombine/or.ll:test23.
---
Diffs of the changes: (+14 -0)
InstructionCombining.cpp | 14 ++++++++++++++
1 files changed, 14 insertions(+)
Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.438
llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.439
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.438 Fri Feb 24
12:05:58 2006
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Sun Feb 26 13:57:54 2006
@@ -2846,6 +2846,20 @@
ConstantInt::get(I.getType(), 1)),
Op0I->getOperand(0));
}
+ } else if (Op0I->getOpcode() == Instruction::Or) {
+ // (X|C1)^C2 -> X^(C1|C2) iff X&~C1 == 0
+ if (MaskedValueIsZero(Op0I->getOperand(0), Op0CI->getZExtValue())) {
+ Constant *NewRHS = ConstantExpr::getOr(Op0CI, RHS);
+ // Anything in both C1 and C2 is known to be zero, remove it from
+ // NewRHS.
+ Constant *CommonBits = ConstantExpr::getAnd(Op0CI, RHS);
+ NewRHS = ConstantExpr::getAnd(NewRHS,
+ ConstantExpr::getNot(CommonBits));
+ WorkList.push_back(Op0I);
+ I.setOperand(0, Op0I->getOperand(0));
+ I.setOperand(1, NewRHS);
+ return &I;
+ }
}
}
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