diff options
Diffstat (limited to 'llvm/lib/Transforms/Utils')
| -rw-r--r-- | llvm/lib/Transforms/Utils/LoopUnroll.cpp | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp index 847224753f4..912f9e0abe7 100644 --- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp +++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp @@ -189,7 +189,8 @@ static bool needToInsertPhisForLCSSA(Loop *L, std::vector<BasicBlock *> Blocks, /// /// PreserveCondBr indicates whether the conditional branch of the LatchBlock /// needs to be preserved. It is needed when we use trip count upper bound to -/// fully unroll the loop. +/// fully unroll the loop. If PreserveOnlyFirst is also set then only the first +/// conditional branch needs to be preserved. /// /// Similarly, TripMultiple divides the number of times that the LatchBlock may /// execute without exiting the loop. @@ -207,10 +208,10 @@ static bool needToInsertPhisForLCSSA(Loop *L, std::vector<BasicBlock *> Blocks, /// DominatorTree if they are non-null. bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, bool Force, bool AllowRuntime, bool AllowExpensiveTripCount, - bool PreserveCondBr, unsigned TripMultiple, LoopInfo *LI, - ScalarEvolution *SE, DominatorTree *DT, - AssumptionCache *AC, OptimizationRemarkEmitter *ORE, - bool PreserveLCSSA) { + bool PreserveCondBr, bool PreserveOnlyFirst, + unsigned TripMultiple, LoopInfo *LI, ScalarEvolution *SE, + DominatorTree *DT, AssumptionCache *AC, + OptimizationRemarkEmitter *ORE, bool PreserveLCSSA) { BasicBlock *Preheader = L->getLoopPreheader(); if (!Preheader) { DEBUG(dbgs() << " Can't unroll; loop preheader-insertion failed.\n"); @@ -550,7 +551,7 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, bool Force, assert(NeedConditional && "NeedCondition cannot be modified by both complete " "unrolling and runtime unrolling"); - NeedConditional = (PreserveCondBr && j); + NeedConditional = (PreserveCondBr && j && !(PreserveOnlyFirst && i != 0)); } else if (j != BreakoutTrip && (TripMultiple == 0 || j % TripMultiple != 0)) { // If we know the trip count or a multiple of it, we can safely use an // unconditional branch for some iterations. |
