[LoopRotate] fix crash encountered with callbr

Summary:
While implementing inlining support for callbr
(https://bugs.llvm.org/show_bug.cgi?id=40722), I hit a crash in Loop
Rotation when trying to build the entire x86 Linux kernel
(drivers/char/random.c). This is a small fix up to r353563.

Test case is drivers/char/random.c (with callbr's inlined), then ran
through creduce, then `opt -opt-bisect-limit=<limit>`, then bugpoint.

Thanks to Craig Topper for immediately spotting the fix, and teaching me
how to fish.

Reviewers: craig.topper, jyknight

Reviewed By: craig.topper

Subscribers: hiraditya, llvm-commits, srhines

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58929

llvm-svn: 355564

1 files changed, 2 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
index a38d34932e1..88c4937cfe1 100644
--- a/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopRotationUtils.cpp
@@ -462,9 +462,8 @@ bool LoopRotate::rotateLoop(Loop *L, bool SimplifiedLatch) {
     for (BasicBlock *ExitPred : ExitPreds) {
       // We only need to split loop exit edges.
       Loop *PredLoop = LI->getLoopFor(ExitPred);
-      if (!PredLoop || PredLoop->contains(Exit))
-        continue;
-      if (isa<IndirectBrInst>(ExitPred->getTerminator()))
+      if (!PredLoop || PredLoop->contains(Exit) ||
+          ExitPred->getTerminator()->isIndirectTerminator())
         continue;
       SplitLatchEdge |= L->getLoopLatch() == ExitPred;
       BasicBlock *ExitSplit = SplitCriticalEdge(