Fix pr4195: When iterating through predecessor blocks, break out of the loop
after finding the (unique) layout predecessor. Sometimes a block may be listed
more than once, and processing it more than once in this loop can lead to
inconsistent values for FtTBB/FtFBB, since the AnalyzeBranch method does not
clear these values. There's no point in continuing the loop regardless.
The testcase for this is reduced from the 2003-05-02-DependentPHI SingleSource
test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71536 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodePlacementOpt.cpp b/lib/CodeGen/CodePlacementOpt.cpp
index 77d23ee..2e1d12d 100644
--- a/lib/CodeGen/CodePlacementOpt.cpp
+++ b/lib/CodeGen/CodePlacementOpt.cpp
@@ -155,10 +155,10 @@
// A fallthrough.
FtMBB = PredMBB;
MachineLoop *PL = MLI->getLoopFor(PredMBB);
- if (PL && (PL == L || PL->getLoopDepth() >= L->getLoopDepth())) {
+ if (PL && (PL == L || PL->getLoopDepth() >= L->getLoopDepth()))
OkToMove = false;
- break;
- }
+
+ break;
}
}