bool Changed = false;
for (Function::iterator I = F.begin(), E = F.end(); I != E; ++I) {
TerminatorInst *TI = I->getTerminator();
- if (TI->getNumSuccessors() > 1)
+ if (TI->getNumSuccessors() > 1 && !isa<IndirectBrInst>(TI))
for (unsigned i = 0, e = TI->getNumSuccessors(); i != e; ++i)
if (SplitCriticalEdge(TI, i, this)) {
++NumBroken;
/// SplitCriticalEdge - If this edge is a critical edge, insert a new node to
/// split the critical edge. This will update DominatorTree and
-/// DominatorFrontier information if it is available, thus calling this pass
-/// will not invalidate any of them. This returns true if the edge was split,
-/// false otherwise. This ensures that all edges to that dest go to one block
-/// instead of each going to a different block.
-//
+/// DominatorFrontier information if it is available, thus calling this pass
+/// will not invalidate either of them. This returns the new block if the edge
+/// was split, null otherwise.
+///
+/// If MergeIdenticalEdges is true (not 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".
+///
+/// It is invalid to call this function on a critical edge that starts at an
+/// IndirectBrInst. Splitting these edges will almost always create an invalid
+/// program because the address of the new block won't be the one that is jumped
+/// to.
+///
BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum,
Pass *P, bool MergeIdenticalEdges) {
if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return 0;
+
+ assert(!isa<IndirectBrInst>(TI) &&
+ "Cannot split critical edge from IndirectBrInst");
+
BasicBlock *TIBB = TI->getParent();
BasicBlock *DestBB = TI->getSuccessor(SuccNum);
if (TIL == DestLoop) {
// Both in the same loop, the NewBB joins loop.
DestLoop->addBasicBlockToLoop(NewBB, LI->getBase());
- } else if (TIL->contains(DestLoop->getHeader())) {
+ } else if (TIL->contains(DestLoop)) {
// Edge from an outer loop to an inner loop. Add to the outer loop.
TIL->addBasicBlockToLoop(NewBB, LI->getBase());
- } else if (DestLoop->contains(TIL->getHeader())) {
+ } else if (DestLoop->contains(TIL)) {
// Edge from an inner loop to an outer loop. Add to the outer loop.
DestLoop->addBasicBlockToLoop(NewBB, LI->getBase());
} else {