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InstCombine: Remove redundant combines 

InstSimplify already handles icmp (X+Y), X (and things like it)
appropriately.  The first thing that InstCombine does is run
InstSimplify on the instruction.

llvm-svn: 216659
This commit is contained in:
David Majnemer 2014-08-28 10:08:37 +00:00
parent 623393f31e
commit 074052b623
1 changed files with 0 additions and 15 deletions
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15
llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
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@ -740,21 +740,6 @@ Instruction *InstCombiner::FoldGEPICmp(GEPOperator *GEPLHS, Value *RHS,
Instruction *InstCombiner::FoldICmpAddOpCst(Instruction &ICI,
Value *X, ConstantInt *CI,
ICmpInst::Predicate Pred) {
// If we have X+0, exit early (simplifying logic below) and let it get folded
// elsewhere. icmp X+0, X -> icmp X, X
if (CI->isZero()) {
bool isTrue = ICmpInst::isTrueWhenEqual(Pred);
return ReplaceInstUsesWith(ICI, ConstantInt::get(ICI.getType(), isTrue));
}
// (X+4) == X -> false.
if (Pred == ICmpInst::ICMP_EQ)
return ReplaceInstUsesWith(ICI, Builder->getFalse());
// (X+4) != X -> true.
if (Pred == ICmpInst::ICMP_NE)
return ReplaceInstUsesWith(ICI, Builder->getTrue());
// From this point on, we know that (X+C <= X) --> (X+C < X) because C != 0,
// so the values can never be equal. Similarly for all other "or equals"
// operators.