[llvm] [LAA] Improve code in findForkedSCEVs (NFC) (PR #140384)
Ramkumar Ramachandra via llvm-commits
llvm-commits at lists.llvm.org
Mon May 19 03:17:42 PDT 2025
https://github.com/artagnon updated https://github.com/llvm/llvm-project/pull/140384
>From 75a85c88a6fbaa4ad89f4d115ff97409fbcae469 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Sat, 17 May 2025 18:33:34 +0100
Subject: [PATCH 1/4] [LAA] Simplify GEP SCEV in findForkedSCEVs (NFC)
---
llvm/lib/Analysis/LoopAccessAnalysis.cpp | 21 +++++++--------------
1 file changed, 7 insertions(+), 14 deletions(-)
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index ab407e945bc53..58083cb06f5f6 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -999,23 +999,16 @@ static void findForkedSCEVs(
break;
}
- // Find the pointer type we need to extend to.
- Type *IntPtrTy = SE->getEffectiveSCEVType(
- SE->getSCEV(GEP->getPointerOperand())->getType());
-
- // 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 *Offset0 = get<0>(OffsetScevs[0]);
+ const SCEV *Offset1 = get<0>(OffsetScevs[1]);
+ const SCEV *Scaled0 = SE->getMulExpr(
+ SE->getSizeOfExpr(Offset0->getType(), SourceTy), Offset0);
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),
+ SE->getSizeOfExpr(Offset1->getType(), SourceTy), Offset1);
+ ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[0]), Scaled0),
NeedsFreeze);
- ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[1]), Scaled2),
+ ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[1]), Scaled1),
NeedsFreeze);
break;
}
>From a450bd52692434b33901ce362c183fb8b3662aac Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Sat, 17 May 2025 19:13:08 +0100
Subject: [PATCH 2/4] [LAA] Fix thinko
---
llvm/lib/Analysis/LoopAccessAnalysis.cpp | 20 ++++++++++++--------
1 file changed, 12 insertions(+), 8 deletions(-)
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 58083cb06f5f6..309d1353f8737 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -1000,16 +1000,20 @@ static void findForkedSCEVs(
}
// Scale up the offsets by the size of the type, then add to the bases.
+ const SCEV *Base0 = get<0>(BaseScevs[0]);
+ const SCEV *Base1 = get<0>(BaseScevs[1]);
const SCEV *Offset0 = get<0>(OffsetScevs[0]);
const SCEV *Offset1 = get<0>(OffsetScevs[1]);
- const SCEV *Scaled0 = SE->getMulExpr(
- SE->getSizeOfExpr(Offset0->getType(), SourceTy), Offset0);
- const SCEV *Scaled1 = SE->getMulExpr(
- SE->getSizeOfExpr(Offset1->getType(), SourceTy), Offset1);
- ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[0]), Scaled0),
- NeedsFreeze);
- ScevList.emplace_back(SE->getAddExpr(get<0>(BaseScevs[1]), Scaled1),
- NeedsFreeze);
+ const SCEV *Scaled0 = SE->getTruncateOrSignExtend(
+ SE->getMulExpr(SE->getSizeOfExpr(Offset0->getType(), SourceTy),
+ Offset0),
+ Base0->getType());
+ const SCEV *Scaled1 = SE->getTruncateOrSignExtend(
+ SE->getMulExpr(SE->getSizeOfExpr(Offset1->getType(), SourceTy),
+ Offset1),
+ Base1->getType());
+ ScevList.emplace_back(SE->getAddExpr(Base0, Scaled0), NeedsFreeze);
+ ScevList.emplace_back(SE->getAddExpr(Base1, Scaled1), NeedsFreeze);
break;
}
case Instruction::Select: {
>From df24c96ef7dacf5f33c01bf2eefe9d29c8f1b043 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Sat, 17 May 2025 19:35:57 +0100
Subject: [PATCH 3/4] [LAA] Improve code in findForkedSCEV
---
llvm/lib/Analysis/LoopAccessAnalysis.cpp | 49 ++++++++++--------------
1 file changed, 20 insertions(+), 29 deletions(-)
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 309d1353f8737..1d8bf5ae84da3 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -999,21 +999,17 @@ static void findForkedSCEVs(
break;
}
- // Scale up the offsets by the size of the type, then add to the bases.
- const SCEV *Base0 = get<0>(BaseScevs[0]);
- const SCEV *Base1 = get<0>(BaseScevs[1]);
- const SCEV *Offset0 = get<0>(OffsetScevs[0]);
- const SCEV *Offset1 = get<0>(OffsetScevs[1]);
- const SCEV *Scaled0 = SE->getTruncateOrSignExtend(
- SE->getMulExpr(SE->getSizeOfExpr(Offset0->getType(), SourceTy),
- Offset0),
- Base0->getType());
- const SCEV *Scaled1 = SE->getTruncateOrSignExtend(
- SE->getMulExpr(SE->getSizeOfExpr(Offset1->getType(), SourceTy),
- Offset1),
- Base1->getType());
- ScevList.emplace_back(SE->getAddExpr(Base0, Scaled0), NeedsFreeze);
- ScevList.emplace_back(SE->getAddExpr(Base1, Scaled1), 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->getTruncateOrSignExtend(
+ SE->getMulExpr(SE->getSizeOfExpr(Offset->getType(), SourceTy),
+ Offset),
+ Base->getType());
+ ScevList.emplace_back(SE->getAddExpr(Base, Scaled), NeedsFreeze);
+ }
break;
}
case Instruction::Select: {
@@ -1023,10 +1019,9 @@ 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;
}
@@ -1039,10 +1034,9 @@ 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;
}
@@ -1069,12 +1063,9 @@ 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:
>From 0fc49fc9b75888f51a36ae452af25f42b3467eb0 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Mon, 19 May 2025 11:16:04 +0100
Subject: [PATCH 4/4] [LAA] Fix SCEV mul at different bitwidth
---
llvm/lib/Analysis/LoopAccessAnalysis.cpp | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index 1d8bf5ae84da3..a006f11ef130a 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -999,15 +999,15 @@ static void findForkedSCEVs(
break;
}
+ Type *PtrTy = GEP->getPointerOperandType();
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->getTruncateOrSignExtend(
- SE->getMulExpr(SE->getSizeOfExpr(Offset->getType(), SourceTy),
- Offset),
- Base->getType());
+ const SCEV *Scaled =
+ SE->getMulExpr(SE->getSizeOfExpr(PtrTy, SourceTy),
+ SE->getTruncateOrSignExtend(Offset, PtrTy));
ScevList.emplace_back(SE->getAddExpr(Base, Scaled), NeedsFreeze);
}
break;
More information about the llvm-commits
mailing list