LoopSimplify bug fix. Handle indirect loop back edges.
Do not call SplitBlockPredecessors on a loop preheader when one of the
predecessors is an indirectbr. Otherwise, you will hit this assert:
!isa<IndirectBrInst>(Preds[i]->getTerminator()) && "Cannot split an edge from an IndirectBrInst"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153134 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index 1b6a19d..0bc185d 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -538,8 +538,7 @@
///
Loop *LoopSimplify::SeparateNestedLoop(Loop *L, LPPassManager &LPM,
BasicBlock *Preheader) {
- // Don't try to separate loops without a preheader (this excludes
- // loop headers which are targeted by an indirectbr).
+ // Don't try to separate loops without a preheader.
if (!Preheader)
return 0;
@@ -554,11 +553,15 @@
// handles the case when a PHI node has multiple instances of itself as
// arguments.
SmallVector<BasicBlock*, 8> OuterLoopPreds;
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
if (PN->getIncomingValue(i) != PN ||
- !L->contains(PN->getIncomingBlock(i)))
+ !L->contains(PN->getIncomingBlock(i))) {
+ // We can't split indirectbr edges.
+ if (isa<IndirectBrInst>(PN->getIncomingBlock(i)->getTerminator()))
+ return 0;
OuterLoopPreds.push_back(PN->getIncomingBlock(i));
-
+ }
+ }
DEBUG(dbgs() << "LoopSimplify: Splitting out a new outer loop\n");
// If ScalarEvolution is around and knows anything about values in