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[LAA] Improve code in findForkedSCEVs (NFC) #140384

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Merged
merged 2 commits into from
Jun 3, 2025
Merged

[LAA] Improve code in findForkedSCEVs (NFC) #140384

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f852718
[LAA] Improve code in findForkedSCEV (NFC)
artagnon May 17, 2025
4a093b1
[LAA] Get effective SCEV type
artagnon Jun 2, 2025
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45 changes: 19 additions & 26 deletions llvm/lib/Analysis/LoopAccessAnalysis.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1001,24 +1001,22 @@ static void findForkedSCEVs(
break;
}

// Find the pointer type we need to extend to.
Type *IntPtrTy = SE->getEffectiveSCEVType(
SE->getSCEV(GEP->getPointerOperand())->getType());
Type *IntPtrTy = SE->getEffectiveSCEVType(GEP->getPointerOperandType());

// Find the size of the type being pointed to. We only have a single
// index term (guarded above) so we don't need to index into arrays or
// structures, just get the size of the scalar value.
const SCEV *Size = SE->getSizeOfExpr(IntPtrTy, SourceTy);

// Scale up the offsets by the size of the type, then add to the bases.
const SCEV *Scaled1 = SE->getMulExpr(
Size, SE->getTruncateOrSignExtend(get<0>(OffsetScevs[0]), IntPtrTy));
const SCEV *Scaled2 = SE->getMulExpr(
Size, SE->getTruncateOrSignExtend(get<0>(OffsetScevs[1]), IntPtrTy));
ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[0]), Scaled1),
NeedsFreeze);
ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[1]), Scaled2),
NeedsFreeze);
for (auto [B, O] : zip(BaseScevs, OffsetScevs)) {
const SCEV *Base = get<0>(B);
const SCEV *Offset = get<0>(O);

// Scale up the offsets by the size of the type, then add to the bases.
const SCEV *Scaled =
SE->getMulExpr(Size, SE->getTruncateOrSignExtend(Offset, IntPtrTy));
ScevList.emplace_back(SE->getAddExpr(Base, Scaled), NeedsFreeze);
}
break;
}
case Instruction::Select: {
Expand All @@ -1028,10 +1026,9 @@ static void findForkedSCEVs(
// then we just bail out and return the generic SCEV.
findForkedSCEVs(SE, L, I->getOperand(1), ChildScevs, Depth);
findForkedSCEVs(SE, L, I->getOperand(2), ChildScevs, Depth);
if (ChildScevs.size() == 2) {
ScevList.push_back(ChildScevs[0]);
ScevList.push_back(ChildScevs[1]);
} else
if (ChildScevs.size() == 2)
append_range(ScevList, ChildScevs);
else
ScevList.emplace_back(Scev, !isGuaranteedNotToBeUndefOrPoison(Ptr));
break;
}
Expand All @@ -1044,10 +1041,9 @@ static void findForkedSCEVs(
findForkedSCEVs(SE, L, I->getOperand(0), ChildScevs, Depth);
findForkedSCEVs(SE, L, I->getOperand(1), ChildScevs, Depth);
}
if (ChildScevs.size() == 2) {
ScevList.push_back(ChildScevs[0]);
ScevList.push_back(ChildScevs[1]);
} else
if (ChildScevs.size() == 2)
append_range(ScevList, ChildScevs);
else
ScevList.emplace_back(Scev, !isGuaranteedNotToBeUndefOrPoison(Ptr));
break;
}
Expand All @@ -1074,12 +1070,9 @@ static void findForkedSCEVs(
break;
}

ScevList.emplace_back(
GetBinOpExpr(Opcode, get<0>(LScevs[0]), get<0>(RScevs[0])),
NeedsFreeze);
ScevList.emplace_back(
GetBinOpExpr(Opcode, get<0>(LScevs[1]), get<0>(RScevs[1])),
NeedsFreeze);
for (auto [L, R] : zip(LScevs, RScevs))
ScevList.emplace_back(GetBinOpExpr(Opcode, get<0>(L), get<0>(R)),
NeedsFreeze);
break;
}
default:
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