If the preheader of the loop was the entry block of the function, make sure
that the exit block of the loop becomes the new entry block of the function.
This was causing a verifier assertion on 252.eon.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13039 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopUnroll.cpp b/lib/Transforms/Scalar/LoopUnroll.cpp
index 266afbb..90de9e9 100644
--- a/lib/Transforms/Scalar/LoopUnroll.cpp
+++ b/lib/Transforms/Scalar/LoopUnroll.cpp
@@ -300,10 +300,15 @@
ChangeExitBlocksFromTo(LI->begin(), LI->end(),
Preheader, LoopExit);
+ // If the preheader was the entry block of this function, move the exit block
+ // to be the new entry of the loop.
+ Function *F = LoopExit->getParent();
+ if (Preheader == &F->front())
+ F->getBasicBlockList().splice(F->begin(), F->getBasicBlockList(), LoopExit);
// Actually delete the blocks now.
- LoopExit->getParent()->getBasicBlockList().erase(Preheader);
- LoopExit->getParent()->getBasicBlockList().erase(BB);
+ F->getBasicBlockList().erase(Preheader);
+ F->getBasicBlockList().erase(BB);
++NumUnrolled;
return true;