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[VPlan] Retrieve vector trip count from BranchOnCount (NFC).

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In preparePlanForMainVectorLoop, the vector trip count may already be
materialized, e.g. when narrowing interleave groups. VPSymbolicValues
should not be accessed after materializing. Instead retrieve the trip
count directly from the branch-on-count. This is NFC at the moment, but
is needed to tighten VPSymbolicValue access verification.
This commit is contained in:
Florian Hahn 2026-02-18 21:08:33 +00:00
parent a6e8de7407
commit cb87d346b4
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GPG Key ID: C8B0D7090F9127E6
1 changed files with 8 additions and 2 deletions
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10
llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
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@ -9069,11 +9069,17 @@ static void preparePlanForMainVectorLoop(VPlan &MainPlan, VPlan &EpiPlan) {
AddFreezeForFindLastIVReductions(MainPlan, true);
AddFreezeForFindLastIVReductions(EpiPlan, false);
VPBasicBlock *MainScalarPH = MainPlan.getScalarPreheader();
VPValue *VectorTC = &MainPlan.getVectorTripCount();
VPValue *VectorTC = nullptr;
auto *Term =
MainPlan.getVectorLoopRegion()->getExitingBasicBlock()->getTerminator();
[[maybe_unused]] bool MatchedTC =
match(Term, m_BranchOnCount(m_VPValue(), m_VPValue(VectorTC)));
assert(MatchedTC && "must match vector trip count");
// If there is a suitable resume value for the canonical induction in the
// scalar (which will become vector) epilogue loop, use it and move it to the
// beginning of the scalar preheader. Otherwise create it below.
VPBasicBlock *MainScalarPH = MainPlan.getScalarPreheader();
auto ResumePhiIter =
find_if(MainScalarPH->phis(), [VectorTC](VPRecipeBase &R) {
return match(&R, m_VPInstruction<Instruction::PHI>(m_Specific(VectorTC),