/// Critical edges are edges from a block with multiple successors to a block
/// with multiple predecessors.
///
-bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum);
+bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
+ bool AllowIdenticalEdges = false);
/// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
/// split the critical edge. This will update DominatorSet, ImmediateDominator,
// Critical edges are edges from a block with multiple successors to a block
// with multiple predecessors.
//
-bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) {
+bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum,
+ bool AllowIdenticalEdges) {
assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
if (TI->getNumSuccessors() == 1) return false;
// If there is more than one predecessor, this is a critical edge...
assert(I != E && "No preds, but we have an edge to the block?");
+ const BasicBlock *FirstPred = *I;
++I; // Skip one edge due to the incoming arc from TI.
- return I != E;
+ if (!AllowIdenticalEdges)
+ return I != E;
+
+ // If AllowIdenticalEdges is true, then we allow this edge to be considered
+ // non-critical iff all preds come from TI's block.
+ for (; I != E; ++I)
+ if (*I != FirstPred) return true;
+ return false;
}
// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
//
bool llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P,
bool MergeIdenticalEdges) {
- if (!isCriticalEdge(TI, SuccNum)) return false;
+ if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return false;
BasicBlock *TIBB = TI->getParent();
BasicBlock *DestBB = TI->getSuccessor(SuccNum);