[llvm] [SCEVPatternMatch] Extend m_scev_AffineAddRec with Loop (PR #141132)
Ramkumar Ramachandra via llvm-commits
llvm-commits at lists.llvm.org
Thu May 22 13:26:04 PDT 2025
https://github.com/artagnon created https://github.com/llvm/llvm-project/pull/141132
None
>From f256b7607df15cbc7fd574b77d59677a773886a9 Mon Sep 17 00:00:00 2001
From: Ramkumar Ramachandra <ramkumar.ramachandra at codasip.com>
Date: Thu, 22 May 2025 19:37:58 +0100
Subject: [PATCH] [SCEVPatternMatch] Extend m_scev_AffineAddRec with Loop
---
.../Analysis/ScalarEvolutionPatternMatch.h | 13 ++++++--
llvm/lib/Transforms/Scalar/IndVarSimplify.cpp | 3 +-
.../Transforms/Scalar/LoopIdiomRecognize.cpp | 32 ++++++++-----------
3 files changed, 25 insertions(+), 23 deletions(-)
diff --git a/llvm/include/llvm/Analysis/ScalarEvolutionPatternMatch.h b/llvm/include/llvm/Analysis/ScalarEvolutionPatternMatch.h
index cfb1b4c6ea6b4..bce10442e3b5c 100644
--- a/llvm/include/llvm/Analysis/ScalarEvolutionPatternMatch.h
+++ b/llvm/include/llvm/Analysis/ScalarEvolutionPatternMatch.h
@@ -14,6 +14,7 @@
#define LLVM_ANALYSIS_SCALAREVOLUTIONPATTERNMATCH_H
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include <type_traits>
namespace llvm {
namespace SCEVPatternMatch {
@@ -162,13 +163,18 @@ template <typename SCEVTy, typename Op0_t, typename Op1_t>
struct SCEVBinaryExpr_match {
Op0_t Op0;
Op1_t Op1;
+ const Loop *L;
- SCEVBinaryExpr_match(Op0_t Op0, Op1_t Op1) : Op0(Op0), Op1(Op1) {}
+ SCEVBinaryExpr_match(Op0_t Op0, Op1_t Op1, const Loop *L = nullptr)
+ : Op0(Op0), Op1(Op1), L(L) {}
bool match(const SCEV *S) const {
auto *E = dyn_cast<SCEVTy>(S);
+ bool LoopMatches = true;
+ if constexpr (std::is_same_v<SCEVTy, SCEVAddRecExpr>)
+ LoopMatches = !L || (E && E->getLoop() == L);
return E && E->getNumOperands() == 2 && Op0.match(E->getOperand(0)) &&
- Op1.match(E->getOperand(1));
+ Op1.match(E->getOperand(1)) && LoopMatches;
}
};
@@ -198,7 +204,8 @@ m_scev_UDiv(const Op0_t &Op0, const Op1_t &Op1) {
template <typename Op0_t, typename Op1_t>
inline SCEVBinaryExpr_match<SCEVAddRecExpr, Op0_t, Op1_t>
-m_scev_AffineAddRec(const Op0_t &Op0, const Op1_t &Op1) {
+m_scev_AffineAddRec(const Op0_t &Op0, const Op1_t &Op1,
+ const Loop *L = nullptr) {
return m_scev_Binary<SCEVAddRecExpr>(Op0, Op1);
}
} // namespace SCEVPatternMatch
diff --git a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
index e774e5fd99cbb..68db70d7abf9b 100644
--- a/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -808,8 +808,7 @@ static bool isLoopCounter(PHINode* Phi, Loop *L,
return false;
const SCEV *S = SE->getSCEV(Phi);
- if (!match(S, m_scev_AffineAddRec(m_SCEV(), m_scev_One())) ||
- cast<SCEVAddRecExpr>(S)->getLoop() != L)
+ if (!match(S, m_scev_AffineAddRec(m_SCEV(), m_scev_One(), L)))
return false;
int LatchIdx = Phi->getBasicBlockIndex(L->getLoopLatch());
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 0d5e0156b22be..2b2f50c7047c9 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -455,8 +455,8 @@ LoopIdiomRecognize::isLegalStore(StoreInst *SI) {
// random store we can't handle.
const SCEV *StoreEv = SE->getSCEV(StorePtr);
const SCEVConstant *Stride;
- if (!match(StoreEv, m_scev_AffineAddRec(m_SCEV(), m_SCEVConstant(Stride))) ||
- cast<SCEVAddRecExpr>(StoreEv)->getLoop() != CurLoop)
+ if (!match(StoreEv,
+ m_scev_AffineAddRec(m_SCEV(), m_SCEVConstant(Stride), CurLoop)))
return LegalStoreKind::None;
// See if the store can be turned into a memset.
@@ -513,8 +513,7 @@ LoopIdiomRecognize::isLegalStore(StoreInst *SI) {
// The store and load must share the same stride.
if (!match(LoadEv,
- m_scev_AffineAddRec(m_SCEV(), m_scev_Specific(Stride))) ||
- cast<SCEVAddRecExpr>(LoadEv)->getLoop() != CurLoop)
+ m_scev_AffineAddRec(m_SCEV(), m_scev_Specific(Stride), CurLoop)))
return LegalStoreKind::None;
// Success. This store can be converted into a memcpy.
@@ -787,11 +786,13 @@ bool LoopIdiomRecognize::processLoopMemCpy(MemCpyInst *MCI,
// See if the load and store pointer expressions are AddRec like {base,+,1} on
// the current loop, which indicates a strided load and store. If we have
// something else, it's a random load or store we can't handle.
- const SCEVAddRecExpr *StoreEv = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(Dest));
- if (!StoreEv || StoreEv->getLoop() != CurLoop || !StoreEv->isAffine())
- return false;
- const SCEVAddRecExpr *LoadEv = dyn_cast<SCEVAddRecExpr>(SE->getSCEV(Source));
- if (!LoadEv || LoadEv->getLoop() != CurLoop || !LoadEv->isAffine())
+ const SCEV *StoreEv = SE->getSCEV(Dest);
+ const SCEV *LoadEv = SE->getSCEV(Source);
+ const APInt *StoreStrideValue, *LoadStrideValue;
+ if (!match(StoreEv, m_scev_AffineAddRec(
+ m_SCEV(), m_scev_APInt(StoreStrideValue), CurLoop)) ||
+ !match(LoadEv, m_scev_AffineAddRec(
+ m_SCEV(), m_scev_APInt(LoadStrideValue), CurLoop)))
return false;
// Reject memcpys that are so large that they overflow an unsigned.
@@ -801,10 +802,6 @@ bool LoopIdiomRecognize::processLoopMemCpy(MemCpyInst *MCI,
// Check if the stride matches the size of the memcpy. If so, then we know
// that every byte is touched in the loop.
- const APInt *StoreStrideValue, *LoadStrideValue;
- if (!match(StoreEv->getOperand(1), m_scev_APInt(StoreStrideValue)) ||
- !match(LoadEv->getOperand(1), m_scev_APInt(LoadStrideValue)))
- return false;
// Huge stride value - give up
if (StoreStrideValue->getBitWidth() > 64 ||
@@ -830,8 +827,8 @@ bool LoopIdiomRecognize::processLoopMemCpy(MemCpyInst *MCI,
return processLoopStoreOfLoopLoad(
Dest, Source, SE->getConstant(Dest->getType(), SizeInBytes),
- MCI->getDestAlign(), MCI->getSourceAlign(), MCI, MCI, StoreEv, LoadEv,
- BECount);
+ MCI->getDestAlign(), MCI->getSourceAlign(), MCI, MCI,
+ cast<SCEVAddRecExpr>(StoreEv), cast<SCEVAddRecExpr>(LoadEv), BECount);
}
/// processLoopMemSet - See if this memset can be promoted to a large memset.
@@ -852,12 +849,11 @@ bool LoopIdiomRecognize::processLoopMemSet(MemSetInst *MSI,
// random store we can't handle.
const SCEV *Ev = SE->getSCEV(Pointer);
const SCEV *PointerStrideSCEV;
- if (!match(Ev, m_scev_AffineAddRec(m_SCEV(), m_SCEV(PointerStrideSCEV)))) {
+ if (!match(Ev, m_scev_AffineAddRec(m_SCEV(), m_SCEV(PointerStrideSCEV),
+ CurLoop))) {
LLVM_DEBUG(dbgs() << " Pointer is not affine, abort\n");
return false;
}
- if (cast<SCEVAddRecExpr>(Ev)->getLoop() != CurLoop)
- return false;
const SCEV *MemsetSizeSCEV = SE->getSCEV(MSI->getLength());
if (!PointerStrideSCEV || !MemsetSizeSCEV)
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