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Swap operands now preserves the semantics of the binary operator by changing

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the opcode of the instruction if possible.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1444 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2001-12-13 00:43:03 +00:00
parent 82d18aa0e4
commit 9a49b210c1
2 changed files with 34 additions and 4 deletions
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lib/VMCore/iOperators.cpp
+26
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@@ -53,6 +53,32 @@ BinaryOperator *BinaryOperator::create(BinaryOps Op, Value *S1, Value *S2,
}
}
// swapOperands - Exchange the two operands to this instruction. This
// instruction is safe to use on any binary instruction and does not
// modify the semantics of the instruction. If the instruction is
// order dependant (SetLT f.e.) the opcode is changed.
//
bool BinaryOperator::swapOperands() {
switch (getOpcode()) {
// Instructions that don't need opcode modification
case Add: case Mul:
case And: case Xor:
case Or:
case SetEQ: case SetNE:
break;
// Instructions that need opcode modification
case SetGT: iType = SetLT; break;
case SetLT: iType = SetGT; break;
case SetGE: iType = SetLE; break;
case SetLE: iType = SetGE; break;
// Error on the side of caution
default:
return true;
}
swap(Operands[0], Operands[1]);
return false;
}
//===----------------------------------------------------------------------===//
// GenericBinaryInst Class