[PATCH] D106244: [LV] Move recurrence backedge fixup code to VPlan::execute (NFC).
Florian Hahn via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Sun Jul 18 12:49:32 PDT 2021
fhahn created this revision.
fhahn added reviewers: gilr, Ayal, rengolin.
Herald added subscribers: tschuett, psnobl, rogfer01, bollu, hiraditya.
fhahn requested review of this revision.
Herald added a subscriber: vkmr.
Herald added a project: LLVM.
As suggested in D105008 <https://reviews.llvm.org/D105008>, move the code that fixes up the backedge value
for first order recurrences to VPlan::execute.
Now all that remains in fixFirstOrderRecurrences is the code responsible
for creating the exit values in the middle block.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D106244
Files:
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
llvm/lib/Transforms/Vectorize/VPlan.cpp
Index: llvm/lib/Transforms/Vectorize/VPlan.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/VPlan.cpp
+++ llvm/lib/Transforms/Vectorize/VPlan.cpp
@@ -815,6 +815,20 @@
for (VPBlockBase *Block : depth_first(Entry))
Block->execute(State);
+ // Fix the latch value of the first-order recurrenxes in the vector loop.
+ VPBasicBlock *Header = Entry->getEntryBasicBlock();
+ for (VPRecipeBase &R : Header->phis()) {
+ if (auto *FOR = dyn_cast<VPFirstOrderRecurrencePHIRecipe>(&R)) {
+ auto *VecPhi = cast<PHINode>(State->get(FOR, 0));
+
+ VPValue *PreviousDef = FOR->getBackedgeValue();
+ Value *Incoming = State->get(PreviousDef, State->UF - 1);
+ VecPhi->addIncoming(
+ Incoming,
+ State->LI->getLoopFor(State->CFG.VPBB2IRBB[Header])->getLoopLatch());
+ }
+ }
+
// Setup branch terminator successors for VPBBs in VPBBsToFix based on
// VPBB's successors.
for (auto VPBB : State->CFG.VPBBsToFix) {
Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -590,8 +590,8 @@
/// Handle all cross-iteration phis in the header.
void fixCrossIterationPHIs(VPTransformState &State);
- /// Fix a first-order recurrence. This is the second phase of vectorizing
- /// this phi node.
+ /// Create the exit value of first order recurrences in the middle block and
+ /// update their users.
void fixFirstOrderRecurrence(VPWidenPHIRecipe *PhiR, VPTransformState &State);
/// Fix a reduction cross-iteration phi. This is the second phase of
@@ -4224,17 +4224,12 @@
// After execution completes the vector loop, we extract the next value of
// the recurrence (x) to use as the initial value in the scalar loop.
- auto *IdxTy = Builder.getInt32Ty();
- auto *VecPhi = cast<PHINode>(State.get(PhiR, 0));
-
- // Fix the latch value of the new recurrence in the vector loop.
- VPValue *PreviousDef = PhiR->getBackedgeValue();
- Value *Incoming = State.get(PreviousDef, UF - 1);
- VecPhi->addIncoming(Incoming, LI->getLoopFor(LoopVectorBody)->getLoopLatch());
-
// Extract the last vector element in the middle block. This will be the
// initial value for the recurrence when jumping to the scalar loop.
+ VPValue *PreviousDef = PhiR->getBackedgeValue();
+ Value *Incoming = State.get(PreviousDef, UF - 1);
auto *ExtractForScalar = Incoming;
+ auto *IdxTy = Builder.getInt32Ty();
if (VF.isVector()) {
auto *One = ConstantInt::get(IdxTy, 1);
Builder.SetInsertPoint(LoopMiddleBlock->getTerminator());
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