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Use IRBuilder while simplifying return instruction.

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llvm-svn: 131580
This commit is contained in:
Devang Patel 2011-05-18 21:33:11 +00:00
parent e410478ca7
commit 3f94bed4e4
1 changed files with 13 additions and 11 deletions
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24
lib/Transforms/Utils/SimplifyCFG.cpp
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@ -62,7 +62,7 @@ class SimplifyCFGOpt {
bool FoldValueComparisonIntoPredecessors(TerminatorInst *TI, bool FoldValueComparisonIntoPredecessors(TerminatorInst *TI,
IRBuilder<> &Builder); IRBuilder<> &Builder);
bool SimplifyReturn(ReturnInst *RI); bool SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder);
bool SimplifyUnwind(UnwindInst *UI, IRBuilder<> &Builder); bool SimplifyUnwind(UnwindInst *UI, IRBuilder<> &Builder);
bool SimplifyUnreachable(UnreachableInst *UI); bool SimplifyUnreachable(UnreachableInst *UI);
bool SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder); bool SimplifySwitch(SwitchInst *SI, IRBuilder<> &Builder);
@ -1370,7 +1370,8 @@ static bool FoldTwoEntryPHINode(PHINode *PN, const TargetData *TD,
/// SimplifyCondBranchToTwoReturns - If we found a conditional branch that goes /// SimplifyCondBranchToTwoReturns - If we found a conditional branch that goes
/// to two returning blocks, try to merge them together into one return, /// to two returning blocks, try to merge them together into one return,
/// introducing a select if the return values disagree. /// introducing a select if the return values disagree.
static bool SimplifyCondBranchToTwoReturns(BranchInst *BI) { static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
IRBuilder<> &Builder) {
assert(BI->isConditional() && "Must be a conditional branch"); assert(BI->isConditional() && "Must be a conditional branch");
BasicBlock *TrueSucc = BI->getSuccessor(0); BasicBlock *TrueSucc = BI->getSuccessor(0);
BasicBlock *FalseSucc = BI->getSuccessor(1); BasicBlock *FalseSucc = BI->getSuccessor(1);
@ -1385,13 +1386,14 @@ static bool SimplifyCondBranchToTwoReturns(BranchInst *BI) {
if (!FalseSucc->getFirstNonPHIOrDbg()->isTerminator()) if (!FalseSucc->getFirstNonPHIOrDbg()->isTerminator())
return false; return false;
Builder.SetInsertPoint(BI);
// Okay, we found a branch that is going to two return nodes. If // Okay, we found a branch that is going to two return nodes. If
// there is no return value for this function, just change the // there is no return value for this function, just change the
// branch into a return. // branch into a return.
if (FalseRet->getNumOperands() == 0) { if (FalseRet->getNumOperands() == 0) {
TrueSucc->removePredecessor(BI->getParent()); TrueSucc->removePredecessor(BI->getParent());
FalseSucc->removePredecessor(BI->getParent()); FalseSucc->removePredecessor(BI->getParent());
ReturnInst::Create(BI->getContext(), 0, BI); Builder.CreateRetVoid();
EraseTerminatorInstAndDCECond(BI); EraseTerminatorInstAndDCECond(BI);
return true; return true;
} }
@ -1434,14 +1436,14 @@ static bool SimplifyCondBranchToTwoReturns(BranchInst *BI) {
} else if (isa<UndefValue>(TrueValue)) { } else if (isa<UndefValue>(TrueValue)) {
TrueValue = FalseValue; TrueValue = FalseValue;
} else { } else {
TrueValue = SelectInst::Create(BrCond, TrueValue, TrueValue = Builder.CreateSelect(BrCond, TrueValue,
FalseValue, "retval", BI); FalseValue, "retval");
} }
} }
Value *RI = !TrueValue ? Value *RI = !TrueValue ?
ReturnInst::Create(BI->getContext(), BI) : Builder.CreateRetVoid() : Builder.CreateRet(TrueValue);
ReturnInst::Create(BI->getContext(), TrueValue, BI);
(void) RI; (void) RI;
DEBUG(dbgs() << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:" DEBUG(dbgs() << "\nCHANGING BRANCH TO TWO RETURNS INTO SELECT:"
@ -2129,7 +2131,7 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, const TargetData *TD) {
return true; return true;
} }
bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI) { bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {
BasicBlock *BB = RI->getParent(); BasicBlock *BB = RI->getParent();
if (!BB->getFirstNonPHIOrDbg()->isTerminator()) return false; if (!BB->getFirstNonPHIOrDbg()->isTerminator()) return false;
@ -2173,7 +2175,7 @@ bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI) {
// Check to see if the non-BB successor is also a return block. // Check to see if the non-BB successor is also a return block.
if (isa<ReturnInst>(BI->getSuccessor(0)->getTerminator()) && if (isa<ReturnInst>(BI->getSuccessor(0)->getTerminator()) &&
isa<ReturnInst>(BI->getSuccessor(1)->getTerminator()) && isa<ReturnInst>(BI->getSuccessor(1)->getTerminator()) &&
SimplifyCondBranchToTwoReturns(BI)) SimplifyCondBranchToTwoReturns(BI, Builder))
return true; return true;
} }
return false; return false;
@ -2671,7 +2673,7 @@ bool SimplifyCFGOpt::run(BasicBlock *BB) {
if (SimplifyCondBranch(BI, Builder)) return true; if (SimplifyCondBranch(BI, Builder)) return true;
} }
} else if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) { } else if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
if (SimplifyReturn(RI)) return true; if (SimplifyReturn(RI, Builder)) return true;
} else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) { } else if (SwitchInst *SI = dyn_cast<SwitchInst>(BB->getTerminator())) {
if (SimplifySwitch(SI, Builder)) return true; if (SimplifySwitch(SI, Builder)) return true;
} else if (UnreachableInst *UI = } else if (UnreachableInst *UI =