Do not infinitely "unroll" single BB loops.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13315 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2004-05-02 05:02:03 +00:00
parent 6e1ef199ab
commit 12fe2b1b82

View File

@ -804,12 +804,12 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
// If this basic block is ONLY a setcc and a branch, and if a predecessor
// branches to us and one of our successors, fold the setcc into the
// predecessor and use logical operations to pick the right destination.
BasicBlock *TrueDest = BI->getSuccessor(0);
BasicBlock *FalseDest = BI->getSuccessor(1);
if (Instruction *Cond = dyn_cast<Instruction>(BI->getCondition()))
if (Cond->getParent() == BB && &BB->front() == Cond &&
Cond->getNext() == BI && Cond->hasOneUse()) {
BasicBlock *TrueDest = BI->getSuccessor(0);
BasicBlock *FalseDest = BI->getSuccessor(1);
Cond->getNext() == BI && Cond->hasOneUse() &&
TrueDest != BB && FalseDest != BB)
for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI!=E; ++PI)
if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator()))
if (PBI->isConditional() && SafeToMergeTerminators(BI, PBI)) {
@ -853,7 +853,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
return SimplifyCFG(BB) | 1;
}
}
}
// If this block ends with a branch instruction, and if there is one
// predecessor, see if the previous block ended with a branch on the same