diff options
Diffstat (limited to 'llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp | 16 |
1 files changed, 9 insertions, 7 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp index d83816a5a51..f60d9903a55 100644 --- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp +++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp @@ -382,13 +382,15 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) { // Find trip count and trip multiple if count is not available unsigned TripCount = 0; unsigned TripMultiple = 1; - // Find "latch trip count". UnrollLoop assumes that control cannot exit - // via the loop latch on any iteration prior to TripCount. The loop may exit - // early via an earlier branch. - BasicBlock *LatchBlock = L->getLoopLatch(); - if (LatchBlock) { - TripCount = SE->getSmallConstantTripCount(L, LatchBlock); - TripMultiple = SE->getSmallConstantTripMultiple(L, LatchBlock); + // If there are multiple exiting blocks but one of them is the latch, use the + // latch for the trip count estimation. Otherwise insist on a single exiting + // block for the trip count estimation. + BasicBlock *ExitingBlock = L->getLoopLatch(); + if (!ExitingBlock || !L->isLoopExiting(ExitingBlock)) + ExitingBlock = L->getExitingBlock(); + if (ExitingBlock) { + TripCount = SE->getSmallConstantTripCount(L, ExitingBlock); + TripMultiple = SE->getSmallConstantTripMultiple(L, ExitingBlock); } // Select an initial unroll count. This may be reduced later based |
