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[LV] Ensure WidenCanonicalIVRecipe is always created in header (NFC).

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The VPWidenCanonicalIVRecipe must always be created in the phi section
of the header block. Use that block as insert point.
This commit is contained in:
Florian Hahn 2021-12-21 15:13:18 +00:00
parent 8dbc7745e5
commit 1a54889f48
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GPG key ID: EEF712BB5E80EBBA
1 changed files with 8 additions and 6 deletions
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14
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
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@ -8446,11 +8446,6 @@ VPValue *VPRecipeBuilder::createBlockInMask(BasicBlock *BB, VPlanPtr &Plan) {
if (!CM.blockNeedsPredicationForAnyReason(BB))
return BlockMaskCache[BB] = BlockMask; // Loop incoming mask is all-one.
// Create the block in mask as the first non-phi instruction in the block.
VPBuilder::InsertPointGuard Guard(Builder);
auto NewInsertionPoint = Builder.getInsertBlock()->getFirstNonPhi();
Builder.setInsertPoint(Builder.getInsertBlock(), NewInsertionPoint);
// Introduce the early-exit compare IV <= BTC to form header block mask.
// This is used instead of IV < TC because TC may wrap, unlike BTC.
// Start by constructing the desired canonical IV.
@ -8458,10 +8453,17 @@ VPValue *VPRecipeBuilder::createBlockInMask(BasicBlock *BB, VPlanPtr &Plan) {
if (Legal->getPrimaryInduction())
IV = Plan->getOrAddVPValue(Legal->getPrimaryInduction());
else {
VPBasicBlock *HeaderVPBB = Plan->getEntry()->getEntryBasicBlock();
auto *IVRecipe = new VPWidenCanonicalIVRecipe();
Builder.getInsertBlock()->insert(IVRecipe, NewInsertionPoint);
HeaderVPBB->insert(IVRecipe, HeaderVPBB->getFirstNonPhi());
IV = IVRecipe;
}
// Create the block in mask as the first non-phi instruction in the block.
VPBuilder::InsertPointGuard Guard(Builder);
auto NewInsertionPoint = Builder.getInsertBlock()->getFirstNonPhi();
Builder.setInsertPoint(Builder.getInsertBlock(), NewInsertionPoint);
VPValue *BTC = Plan->getOrCreateBackedgeTakenCount();
bool TailFolded = !CM.isScalarEpilogueAllowed();