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Expand the pass to unify all of the unwind blocks as well

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8456 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2003-09-10 20:34:51 +00:00
parent d0b52cf3e7
commit f46057be77
2 changed files with 42 additions and 17 deletions
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34
lib/Transforms/Utils/UnifyFunctionExitNodes.cpp
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@ -18,6 +18,10 @@
static RegisterOpt<UnifyFunctionExitNodes>
X("mergereturn", "Unify function exit nodes");
Pass *createUnifyFunctionExitNodesPass() {
return new UnifyFunctionExitNodes();
}
void UnifyFunctionExitNodes::getAnalysisUsage(AnalysisUsage &AU) const{
// We preserve the non-critical-edgeness property
AU.addPreservedID(BreakCriticalEdgesID);
@ -34,15 +38,36 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
// return.
//
std::vector<BasicBlock*> ReturningBlocks;
std::vector<BasicBlock*> UnwindingBlocks;
for(Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
if (isa<ReturnInst>(I->getTerminator()))
ReturningBlocks.push_back(I);
else if (isa<UnwindInst>(I->getTerminator()))
UnwindingBlocks.push_back(I);
// Handle unwinding blocks first...
if (UnwindingBlocks.empty()) {
UnwindBlock = 0;
} else if (UnwindingBlocks.size() == 1) {
UnwindBlock = UnwindingBlocks.front();
} else {
UnwindBlock = new BasicBlock("UnifiedUnwindBlock", &F);
UnwindBlock->getInstList().push_back(new UnwindInst());
for (std::vector<BasicBlock*>::iterator I = UnwindingBlocks.begin(),
E = UnwindingBlocks.end(); I != E; ++I) {
BasicBlock *BB = *I;
BB->getInstList().pop_back(); // Remove the return insn
BB->getInstList().push_back(new BranchInst(UnwindBlock));
}
}
// Now handle return blocks...
if (ReturningBlocks.empty()) {
ExitNode = 0;
ReturnBlock = 0;
return false; // No blocks return
} else if (ReturningBlocks.size() == 1) {
ExitNode = ReturningBlocks.front(); // Already has a single return block
ReturnBlock = ReturningBlocks.front(); // Already has a single return block
return false;
}
@ -50,7 +75,7 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
// node (if the function returns a value), and convert all of the return
// instructions into unconditional branches.
//
BasicBlock *NewRetBlock = new BasicBlock("UnifiedExitNode", &F);
BasicBlock *NewRetBlock = new BasicBlock("UnifiedReturnBlock", &F);
PHINode *PN = 0;
if (F.getReturnType() != Type::VoidTy) {
@ -77,7 +102,6 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
BB->getInstList().pop_back(); // Remove the return insn
BB->getInstList().push_back(new BranchInst(NewRetBlock));
}
ExitNode = NewRetBlock;
ReturnBlock = NewRetBlock;
return true;
}