Author: Philip Reames Date: 2020-12-15T18:46:32-08:00 New Revision: af7ef895d4951cd41c5e055c84469b4fd229d50c
URL: https://github.com/llvm/llvm-project/commit/af7ef895d4951cd41c5e055c84469b4fd229d50c DIFF: https://github.com/llvm/llvm-project/commit/af7ef895d4951cd41c5e055c84469b4fd229d50c.diff LOG: [LV] Extend dead instruction detection to multiple exiting blocks Given we haven't yet enabled multiple exiting blocks, this is currently non functional, but it's an obvious extension which cleans up a later patch. I don't think this is worth review (as it's pretty obvious), if anyone disagrees, feel feel to revert or comment and I will. Added: Modified: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp Removed: ################################################################################ diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp index 6e506a4d71a4..cbeb6a32825f 100644 --- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp +++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp @@ -7472,16 +7472,23 @@ void LoopVectorizationPlanner::executePlan(InnerLoopVectorizer &ILV, void LoopVectorizationPlanner::collectTriviallyDeadInstructions( SmallPtrSetImpl<Instruction *> &DeadInstructions) { - BasicBlock *Latch = OrigLoop->getLoopLatch(); - // We create new control-flow for the vectorized loop, so the original - // condition will be dead after vectorization if it's only used by the - // branch. - auto *Cmp = dyn_cast<Instruction>(Latch->getTerminator()->getOperand(0)); - if (Cmp && Cmp->hasOneUse()) { - DeadInstructions.insert(Cmp); + // We create new control-flow for the vectorized loop, so the original exit + // conditions will be dead after vectorization if it's only used by the + // terminator + SmallVector<BasicBlock*> ExitingBlocks; + OrigLoop->getExitingBlocks(ExitingBlocks); + for (auto *BB : ExitingBlocks) { + auto *Cmp = dyn_cast<Instruction>(BB->getTerminator()->getOperand(0)); + if (!Cmp || !Cmp->hasOneUse()) + continue; + + // TODO: we should introduce a getUniqueExitingBlocks on Loop + if (!DeadInstructions.insert(Cmp).second) + continue; // The operands of the icmp is often a dead trunc, used by IndUpdate. + // TODO: can recurse through operands in general for (Value *Op : Cmp->operands()) { if (isa<TruncInst>(Op) && Op->hasOneUse()) DeadInstructions.insert(cast<Instruction>(Op)); @@ -7491,6 +7498,7 @@ void LoopVectorizationPlanner::collectTriviallyDeadInstructions( // We create new "steps" for induction variable updates to which the original // induction variables map. An original update instruction will be dead if // all its users except the induction variable are dead. + auto *Latch = OrigLoop->getLoopLatch(); for (auto &Induction : Legal->getInductionVars()) { PHINode *Ind = Induction.first; auto *IndUpdate = cast<Instruction>(Ind->getIncomingValueForBlock(Latch)); _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
