diff options
Diffstat (limited to 'llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp')
| -rw-r--r-- | llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp index da3ac06ab46..55494440470 100644 --- a/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp +++ b/llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp @@ -4146,8 +4146,8 @@ bool SLPVectorizerPass::tryToVectorizeList(ArrayRef<Value *> VL, BoUpSLP &R, if (AllowReorder && R.shouldReorder()) { // Conceptually, there is nothing actually preventing us from trying to // reorder a larger list. In fact, we do exactly this when vectorizing - // reductions. However, at this point, we only expect to get here from - // tryToVectorizePair(). + // reductions. However, at this point, we only expect to get here when + // there are exactly two operations. assert(Ops.size() == 2); assert(BuildVectorSlice.empty()); Value *ReorderedOps[] = {Ops[1], Ops[0]}; @@ -4904,7 +4904,13 @@ bool SLPVectorizerPass::vectorizeChainsInBlock(BasicBlock *BB, BoUpSLP &R) { // Try to vectorize them. unsigned NumElts = (SameTypeIt - IncIt); DEBUG(errs() << "SLP: Trying to vectorize starting at PHIs (" << NumElts << ")\n"); - if (NumElts > 1 && tryToVectorizeList(makeArrayRef(IncIt, NumElts), R)) { + // The order in which the phi nodes appear in the program does not matter. + // So allow tryToVectorizeList to reorder them if it is beneficial. This + // is done when there are exactly two elements since tryToVectorizeList + // asserts that there are only two values when AllowReorder is true. + bool AllowReorder = NumElts == 2; + if (NumElts > 1 && tryToVectorizeList(makeArrayRef(IncIt, NumElts), R, + None, AllowReorder)) { // Success start over because instructions might have been changed. HaveVectorizedPhiNodes = true; Changed = true; |
