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Add a minor optimization: if we haven't changed the operands of an

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add, there is no need to scan the world to find the same add again.
This invalidates the previous testcase, which wasn't wonderful anyway,
because it needed a run of instcombine to permute the use-lists in 
just the right way to before GVN was run (so it was really fragile).
Not a big loss.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90973 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-12-09 17:27:45 +00:00
parent 16f1692dca
commit 4d3a16f81b
2 changed files with 4 additions and 66 deletions
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4
lib/Analysis/PHITransAddr.cpp
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@ -275,6 +275,10 @@ Value *PHITransAddr::PHITranslateSubExpr(Value *V, BasicBlock *CurBB,
RemoveInstInputs(LHS, InstInputs);
return AddAsInput(Res);
}
// If we didn't modify the add, just return it.
if (LHS == Inst->getOperand(0) && RHS == Inst->getOperand(1))
return Inst;
// Otherwise, see if we have this add available somewhere.
for (Value::use_iterator UI = LHS->use_begin(), E = LHS->use_end();