add option to isCriticalEdge

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31258 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2006-10-28 06:58:17 +00:00
parent 0997fadc37
commit b57de3328d
2 changed files with 14 additions and 4 deletions

View File

@ -57,7 +57,8 @@ void RemoveSuccessor(TerminatorInst *TI, unsigned SuccNum);
/// Critical edges are edges from a block with multiple successors to a block /// Critical edges are edges from a block with multiple successors to a block
/// with multiple predecessors. /// 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 /// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
/// split the critical edge. This will update DominatorSet, ImmediateDominator, /// split the critical edge. This will update DominatorSet, ImmediateDominator,

View File

@ -84,7 +84,8 @@ bool BreakCriticalEdges::runOnFunction(Function &F) {
// Critical edges are edges from a block with multiple successors to a block // Critical edges are edges from a block with multiple successors to a block
// with multiple predecessors. // 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!"); assert(SuccNum < TI->getNumSuccessors() && "Illegal edge specification!");
if (TI->getNumSuccessors() == 1) return false; if (TI->getNumSuccessors() == 1) return false;
@ -93,8 +94,16 @@ bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) {
// If there is more than one predecessor, this is a critical edge... // 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?"); 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. ++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 // SplitCriticalEdge - If this edge is a critical edge, insert a new node to
@ -106,7 +115,7 @@ bool llvm::isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum) {
// //
bool llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P, bool llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P,
bool MergeIdenticalEdges) { bool MergeIdenticalEdges) {
if (!isCriticalEdge(TI, SuccNum)) return false; if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return false;
BasicBlock *TIBB = TI->getParent(); BasicBlock *TIBB = TI->getParent();
BasicBlock *DestBB = TI->getSuccessor(SuccNum); BasicBlock *DestBB = TI->getSuccessor(SuccNum);