diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp index 59408ffe7a7..2b432426b24 100644 --- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp +++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp @@ -470,8 +470,9 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count, bool UseEpilogRemainder, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT, bool PreserveLCSSA) { - // for now, only unroll loops that contain a single exit - if (!UnrollRuntimeMultiExit && !L->getExitingBlock()) + bool hasMultipleExitingBlocks = !L->getExitingBlock(); + // Support only single exiting block unless UnrollRuntimeMultiExit is true. + if (!UnrollRuntimeMultiExit && hasMultipleExitingBlocks) return false; // Make sure the loop is in canonical form. @@ -516,6 +517,13 @@ bool llvm::UnrollRuntimeLoopRemainder(Loop *L, unsigned Count, // connectEpilog. if (!LatchExit->getSinglePredecessor()) return false; + // FIXME: We bail out of multi-exit unrolling when epilog loop is generated + // and L is an inner loop. This is because in presence of multiple exits, the + // outer loop is incorrect: we do not add the EpilogPreheader and exit to the + // outer loop. This is automatically handled in the prolog case, so we do not + // have that bug in prolog generation. + if (hasMultipleExitingBlocks && UseEpilogRemainder && L->getParentLoop()) + return false; // Use Scalar Evolution to compute the trip count. This allows more loops to // be unrolled than relying on induction var simplification. if (!SE) |
