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-rw-r--r--llvm/lib/Transforms/Utils/LoopSimplify.cpp16
1 files changed, 10 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index b2aa20bc0f8..954e8038dfb 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -27,6 +27,9 @@
// to transform the loop and make these guarantees. Client code should check
// that these conditions are true before relying on them.
//
+// Similar complications arise from callbr instructions, particularly in
+// asm-goto where blockaddress expressions are used.
+//
// Note that the simplifycfg pass will clean up blocks which are split out but
// end up being unnecessary, so usage of this pass should not pessimize
// generated code.
@@ -123,10 +126,11 @@ BasicBlock *llvm::InsertPreheaderForLoop(Loop *L, DominatorTree *DT,
PI != PE; ++PI) {
BasicBlock *P = *PI;
if (!L->contains(P)) { // Coming in from outside the loop?
- // If the loop is branched to from an indirect branch, we won't
+ // If the loop is branched to from an indirect terminator, we won't
// be able to fully transform the loop, because it prohibits
// edge splitting.
- if (isa<IndirectBrInst>(P->getTerminator())) return nullptr;
+ if (P->getTerminator()->isIndirectTerminator())
+ return nullptr;
// Keep track of it.
OutsideBlocks.push_back(P);
@@ -235,8 +239,8 @@ static Loop *separateNestedLoop(Loop *L, BasicBlock *Preheader,
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
if (PN->getIncomingValue(i) != PN ||
!L->contains(PN->getIncomingBlock(i))) {
- // We can't split indirectbr edges.
- if (isa<IndirectBrInst>(PN->getIncomingBlock(i)->getTerminator()))
+ // We can't split indirect control flow edges.
+ if (PN->getIncomingBlock(i)->getTerminator()->isIndirectTerminator())
return nullptr;
OuterLoopPreds.push_back(PN->getIncomingBlock(i));
}
@@ -357,8 +361,8 @@ static BasicBlock *insertUniqueBackedgeBlock(Loop *L, BasicBlock *Preheader,
for (pred_iterator I = pred_begin(Header), E = pred_end(Header); I != E; ++I){
BasicBlock *P = *I;
- // Indirectbr edges cannot be split, so we must fail if we find one.
- if (isa<IndirectBrInst>(P->getTerminator()))
+ // Indirect edges cannot be split, so we must fail if we find one.
+ if (P->getTerminator()->isIndirectTerminator())
return nullptr;
if (P != Preheader) BackedgeBlocks.push_back(P);
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