diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils/LoopUnroll.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LoopUnroll.cpp | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp index ad4c388e406..44dde1b51cf 100644 --- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp +++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp @@ -221,6 +221,12 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, // Are we eliminating the loop control altogether? bool CompletelyUnroll = Count == TripCount; + SmallVector<BasicBlock *, 4> ExitBlocks; + L->getExitBlocks(ExitBlocks); + Loop *ParentL = L->getParentLoop(); + bool AllExitsAreInsideParentLoop = !ParentL || + std::all_of(ExitBlocks.begin(), ExitBlocks.end(), + [&](BasicBlock *BB) { return ParentL->contains(BB); }); // We assume a run-time trip count if the compiler cannot // figure out the loop trip count and the unroll-runtime @@ -544,7 +550,7 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, if (!OuterL && !CompletelyUnroll) OuterL = L; if (OuterL) { - simplifyLoop(OuterL, DT, LI, PP, SE, AC); + bool Simplified = simplifyLoop(OuterL, DT, LI, PP, SE, AC); // LCSSA must be performed on the outermost affected loop. The unrolled // loop's last loop latch is guaranteed to be in the outermost loop after @@ -554,7 +560,11 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, while (OuterL->getParentLoop() != LatchLoop) OuterL = OuterL->getParentLoop(); - formLCSSARecursively(*OuterL, *DT, LI, SE); + if (CompletelyUnroll && (!AllExitsAreInsideParentLoop || Simplified)) + formLCSSARecursively(*OuterL, *DT, LI, SE); + else + assert(OuterL->isLCSSAForm(*DT) && + "Loops should be in LCSSA form after loop-unroll."); } } |
