Nick Lewycky pointed out that this code makes changes unconditionally.

[oota-llvm.git] / lib / Transforms / Utils / LoopSimplify.cpp

diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp
index 63708b14b4d7e35c865b33422257b29986c225f0..7fcc5f748a72e7e083437540ae191d70e6684a66 100644 (file)
--- a/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/lib/Transforms/Utils/LoopSimplify.cpp
@@ -109,7 +109,7 @@ X("loopsimplify", "Canonicalize natural loops", true);
 const PassInfo *const llvm::LoopSimplifyID = &X;
 Pass *llvm::createLoopSimplifyPass() { return new LoopSimplify(); }
 
-/// runOnFunction - Run down all loops in the CFG (recursively, but we could do
+/// runOnLoop - Run down all loops in the CFG (recursively, but we could do
 /// it in any convenient order) inserting preheaders...
 ///
 bool LoopSimplify::runOnLoop(Loop *l, LPPassManager &LPM) {
@@ -241,7 +241,14 @@ ReprocessLoop:
   // loop-invariant instructions out of the way to open up more
   // opportunities, and the disadvantage of having the responsibility
   // to preserve dominator information.
-  if (ExitBlocks.size() > 1 && L->getUniqueExitBlock()) {
+  bool UniqueExit = true;
+  if (!ExitBlocks.empty())
+    for (unsigned i = 1, e = ExitBlocks.size(); i != e; ++i)
+      if (ExitBlocks[i] != ExitBlocks[0]) {
+        UniqueExit = false;
+        break;
+      }
+  if (UniqueExit) {
     SmallVector<BasicBlock*, 8> ExitingBlocks;
     L->getExitingBlocks(ExitingBlocks);
     for (unsigned i = 0, e = ExitingBlocks.size(); i != e; ++i) {
@@ -464,8 +471,13 @@ Loop *LoopSimplify::SeparateNestedLoop(Loop *L, LPPassManager &LPM) {
   SmallVector<BasicBlock*, 8> OuterLoopPreds;
   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));
+    }
 
   BasicBlock *Header = L->getHeader();
   BasicBlock *NewBB = SplitBlockPredecessors(Header, &OuterLoopPreds[0],