diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Transforms/Utils/LoopSimplify.cpp | 21 |
1 files changed, 14 insertions, 7 deletions
diff --git a/lib/Transforms/Utils/LoopSimplify.cpp b/lib/Transforms/Utils/LoopSimplify.cpp index 6d5f16ca33..07cc43f885 100644 --- a/lib/Transforms/Utils/LoopSimplify.cpp +++ b/lib/Transforms/Utils/LoopSimplify.cpp @@ -309,6 +309,7 @@ ReprocessLoop: // Attempt to hoist out all instructions except for the // comparison and the branch. bool AllInvariant = true; + bool AnyInvariant = false; for (BasicBlock::iterator I = ExitingBlock->begin(); &*I != BI; ) { Instruction *Inst = I++; // Skip debug info intrinsics. @@ -316,12 +317,19 @@ ReprocessLoop: continue; if (Inst == CI) continue; - if (!L->makeLoopInvariant(Inst, Changed, - Preheader ? Preheader->getTerminator() : 0)) { + if (!L->makeLoopInvariant(Inst, AnyInvariant, + Preheader ? Preheader->getTerminator() : 0)) { AllInvariant = false; break; } } + if (AnyInvariant) { + Changed = true; + // The loop disposition of all SCEV expressions that depend on any + // hoisted values have also changed. + if (SE) + SE->forgetLoopDispositions(L); + } if (!AllInvariant) continue; // The block has now been cleared of all instructions except for @@ -334,11 +342,10 @@ ReprocessLoop: DEBUG(dbgs() << "LoopSimplify: Eliminating exiting block " << ExitingBlock->getName() << "\n"); - // If any reachable control flow within this loop has changed, notify - // ScalarEvolution. Currently assume the parent loop doesn't change - // (spliting edges doesn't count). If blocks, CFG edges, or other values - // in the parent loop change, then we need call to forgetLoop() for the - // parent instead. + // Notify ScalarEvolution before deleting this block. Currently assume the + // parent loop doesn't change (spliting edges doesn't count). If blocks, + // CFG edges, or other values in the parent loop change, then we need call + // to forgetLoop() for the parent instead. if (SE) SE->forgetLoop(L); |