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Propagating constants to arguments can make other arguments constant. For now

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do something dumb, and inefficient, but more complete.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9542 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-10-27 21:09:00 +00:00
parent e01fcfbdef
commit 2e8dfb8221
1 changed files with 15 additions and 5 deletions
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20
lib/Transforms/IPO/IPConstantPropagation.cpp
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@ -40,9 +40,17 @@ Pass *createIPConstantPropagationPass() { return new IPCP(); }
bool IPCP::run(Module &M) {
bool Changed = false;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal() && I->hasInternalLinkage())
Changed |= processFunction(*I);
bool LocalChange = true;
// FIXME: instead of using smart algorithms, we just iterate until we stop
// making changes.
while (LocalChange) {
LocalChange = false;
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I)
if (!I->isExternal() && I->hasInternalLinkage())
LocalChange |= processFunction(*I);
Changed |= LocalChange;
}
return Changed;
}
@ -99,15 +107,17 @@ bool IPCP::processFunction(Function &F) {
// If we got to this point, there is a constant argument!
assert(NumNonconstant != ArgumentConstants.size());
Function::aiterator AI = F.abegin();
bool MadeChange = false;
for (unsigned i = 0, e = ArgumentConstants.size(); i != e; ++i, ++AI)
// Do we have a constant argument!?
if (!ArgumentConstants[i].second) {
if (!ArgumentConstants[i].second && !AI->use_empty()) {
assert(ArgumentConstants[i].first && "Unknown constant value!");
Value *V = ArgumentConstants[i].first;
if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(V))
V = CPR->getValue();
AI->replaceAllUsesWith(V);
++NumArgumentsProped;
MadeChange = true;
}
return true;
return MadeChange;
}