Fix bug: LoopPreheaders/2003-05-12-PreheaderExitOfChild.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6153 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index d5988b1..7576b01 100644
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -167,6 +167,19 @@
return NewBB;
}
+// ChangeExitBlock - This recursive function is used to change any exit blocks
+// that use OldExit to use NewExit instead. This is recursive because children
+// may need to be processed as well.
+//
+static void ChangeExitBlock(Loop *L, BasicBlock *OldExit, BasicBlock *NewExit) {
+ if (L->hasExitBlock(OldExit)) {
+ L->changeExitBlock(OldExit, NewExit);
+ const std::vector<Loop*> &SubLoops = L->getSubLoops();
+ for (unsigned i = 0, e = SubLoops.size(); i != e; ++i)
+ ChangeExitBlock(SubLoops[i], OldExit, NewExit);
+ }
+}
+
/// InsertPreheaderForLoop - Once we discover that a loop doesn't have a
/// preheader, this method is called to insert one. This method has two phases:
@@ -197,18 +210,19 @@
// If the header for the loop used to be an exit node for another loop, then
// we need to update this to know that the loop-preheader is now the exit
// node. Note that the only loop that could have our header as an exit node
- // is a sibling loop, ie, one with the same parent loop.
+ // is a sibling loop, ie, one with the same parent loop, or one if it's
+ // children.
+ //
const std::vector<Loop*> *ParentSubLoops;
if (Loop *Parent = L->getParentLoop())
ParentSubLoops = &Parent->getSubLoops();
else // Must check top-level loops...
ParentSubLoops = &getAnalysis<LoopInfo>().getTopLevelLoops();
- // Loop over all sibling loops, performing the substitution...
+ // Loop over all sibling loops, performing the substitution (recursively to
+ // include child loops)...
for (unsigned i = 0, e = ParentSubLoops->size(); i != e; ++i)
- if ((*ParentSubLoops)[i]->hasExitBlock(Header))
- (*ParentSubLoops)[i]->changeExitBlock(Header, NewBB);
-
+ ChangeExitBlock((*ParentSubLoops)[i], Header, NewBB);
DominatorSet &DS = getAnalysis<DominatorSet>(); // Update dominator info
{