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Expose a smarter way to break critical edges.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31256 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2006-10-28 06:44:56 +00:00
parent f6de8ad1a2
commit 27e1f90d85
2 changed files with 35 additions and 9 deletions
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15
include/llvm/Transforms/Utils/BasicBlockUtils.h
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@ -63,9 +63,15 @@ bool isCriticalEdge(const TerminatorInst *TI, unsigned SuccNum);
/// split the critical edge. This will update DominatorSet, ImmediateDominator,
/// DominatorTree, and DominatorFrontier information if it is available, thus
/// calling this pass will not invalidate either of them. This returns true if
/// the edge was split, false otherwise.
/// the edge was split, false otherwise. If MergeIdenticalEdges is true (the
/// default), *all* edges from TI to the specified successor will be merged into
/// the same critical edge block. This is most commonly interesting with switch
/// instructions, which may have many edges to any one destination. This
/// ensures that all edges to that dest go to one block instead of each going to
/// a different block, but isn't the standard definition of a "critical edge".
///
bool SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0);
bool SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, Pass *P = 0,
bool MergeIdenticalEdges = false);
inline bool SplitCriticalEdge(BasicBlock *BB, succ_iterator SI, Pass *P = 0) {
return SplitCriticalEdge(BB->getTerminator(), SI.getSuccessorIndex(), P);
@ -89,13 +95,14 @@ inline bool SplitCriticalEdge(BasicBlock *Succ, pred_iterator PI, Pass *P = 0) {
/// and return true, otherwise return false. This method requires that there be
/// an edge between the two blocks. If P is specified, it updates the analyses
/// described above.
inline bool SplitCriticalEdge(BasicBlock *Src, BasicBlock *Dst, Pass *P = 0) {
inline bool SplitCriticalEdge(BasicBlock *Src, BasicBlock *Dst, Pass *P = 0,
bool MergeIdenticalEdges = false) {
TerminatorInst *TI = Src->getTerminator();
unsigned i = 0;
while (1) {
assert(i != TI->getNumSuccessors() && "Edge doesn't exist!");
if (TI->getSuccessor(i) == Dst)
return SplitCriticalEdge(TI, i, P);
return SplitCriticalEdge(TI, i, P, MergeIdenticalEdges);
++i;
}
}