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.

llvm-svn: 71536

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/CodePlacementOpt.cpp b/llvm/lib/CodeGen/CodePlacementOpt.cpp
index 77d23eed6c9..2e1d12d2346 100644
--- a/llvm/lib/CodeGen/CodePlacementOpt.cpp
+++ b/llvm/lib/CodeGen/CodePlacementOpt.cpp
@@ -155,10 +155,10 @@ bool CodePlacementOpt::OptimizeIntraLoopEdges() {
         // 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;
       }
     }