Do not infinitely "unroll" single BB loops.
llvm-svn: 13315
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index a1b917f..a5153d6 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -804,12 +804,12 @@
// 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 @@
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