[delinearize] use SCEV exprs in getIndexExpressionsFromGEP #162888
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@llvm/pr-subscribers-llvm-analysis Author: Sebastian Pop (sebpop) Changesclean up interface of getIndexExpressionsFromGEP to get SCEV expressions instead of int for Sizes of the arrays. Full diff: https://github.com/llvm/llvm-project/pull/162888.diff 5 Files Affected:
diff --git a/llvm/include/llvm/Analysis/Delinearization.h b/llvm/include/llvm/Analysis/Delinearization.h
index 434cfb61699d6..9c729b5cf18c8 100644
--- a/llvm/include/llvm/Analysis/Delinearization.h
+++ b/llvm/include/llvm/Analysis/Delinearization.h
@@ -145,15 +145,15 @@ bool delinearizeFixedSizeArray(ScalarEvolution &SE, const SCEV *Expr,
///
/// This function optimistically assumes the GEP references into a fixed size
/// array. If this is actually true, this function returns a list of array
-/// subscript expressions in \p Subscripts and a list of integers describing
-/// the size of the individual array dimensions in \p Sizes. Both lists have
-/// either equal length or the size list is one element shorter in case there
-/// is no known size available for the outermost array dimension. Returns true
-/// if successful and false otherwise.
+/// subscript expressions in \p Subscripts and a list of SCEV expressions
+/// describing the size of the individual array dimensions in \p Sizes. Both
+/// lists have either equal length or the size list is one element shorter in
+/// case there is no known size available for the outermost array dimension.
+/// Returns true if successful and false otherwise.
bool getIndexExpressionsFromGEP(ScalarEvolution &SE,
const GetElementPtrInst *GEP,
SmallVectorImpl<const SCEV *> &Subscripts,
- SmallVectorImpl<int> &Sizes);
+ SmallVectorImpl<const SCEV *> &Sizes);
/// Implementation of fixed size array delinearization. Try to delinearize
/// access function for a fixed size multi-dimensional array, by deriving
@@ -164,7 +164,7 @@ bool getIndexExpressionsFromGEP(ScalarEvolution &SE,
bool tryDelinearizeFixedSizeImpl(ScalarEvolution *SE, Instruction *Inst,
const SCEV *AccessFn,
SmallVectorImpl<const SCEV *> &Subscripts,
- SmallVectorImpl<int> &Sizes);
+ SmallVectorImpl<const SCEV *> &Sizes);
struct DelinearizationPrinterPass
: public PassInfoMixin<DelinearizationPrinterPass> {
diff --git a/llvm/lib/Analysis/Delinearization.cpp b/llvm/lib/Analysis/Delinearization.cpp
index 4064b25d9d4e7..f438a9bd9ecdd 100644
--- a/llvm/lib/Analysis/Delinearization.cpp
+++ b/llvm/lib/Analysis/Delinearization.cpp
@@ -659,7 +659,7 @@ bool llvm::delinearizeFixedSizeArray(ScalarEvolution &SE, const SCEV *Expr,
bool llvm::getIndexExpressionsFromGEP(ScalarEvolution &SE,
const GetElementPtrInst *GEP,
SmallVectorImpl<const SCEV *> &Subscripts,
- SmallVectorImpl<int> &Sizes) {
+ SmallVectorImpl<const SCEV *> &Sizes) {
assert(Subscripts.empty() && Sizes.empty() &&
"Expected output lists to be empty on entry to this function.");
assert(GEP && "getIndexExpressionsFromGEP called with a null GEP");
@@ -690,7 +690,8 @@ bool llvm::getIndexExpressionsFromGEP(ScalarEvolution &SE,
Subscripts.push_back(Expr);
if (!(DroppedFirstDim && i == 2))
- Sizes.push_back(ArrayTy->getNumElements());
+ Sizes.push_back(SE.getConstant(Expr->getType(),
+ ArrayTy->getNumElements()));
Ty = ArrayTy->getElementType();
}
@@ -706,7 +707,7 @@ bool llvm::getIndexExpressionsFromGEP(ScalarEvolution &SE,
bool llvm::tryDelinearizeFixedSizeImpl(
ScalarEvolution *SE, Instruction *Inst, const SCEV *AccessFn,
- SmallVectorImpl<const SCEV *> &Subscripts, SmallVectorImpl<int> &Sizes) {
+ SmallVectorImpl<const SCEV *> &Subscripts, SmallVectorImpl<const SCEV *> &Sizes) {
Value *SrcPtr = getLoadStorePointerOperand(Inst);
// Check the simple case where the array dimensions are fixed size.
diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 8d20b0e10305b..7dd0bea75c847 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -3504,8 +3504,8 @@ bool DependenceInfo::tryDelinearizeFixedSize(
"expected src and dst scev unknowns to be equal");
});
- SmallVector<int, 4> SrcSizes;
- SmallVector<int, 4> DstSizes;
+ SmallVector<const SCEV *, 4> SrcSizes;
+ SmallVector<const SCEV *, 4> DstSizes;
if (!tryDelinearizeFixedSizeImpl(SE, Src, SrcAccessFn, SrcSubscripts,
SrcSizes) ||
!tryDelinearizeFixedSizeImpl(SE, Dst, DstAccessFn, DstSubscripts,
@@ -3513,7 +3513,7 @@ bool DependenceInfo::tryDelinearizeFixedSize(
return false;
// Check that the two size arrays are non-empty and equal in length and
- // value.
+ // value. SCEV expressions are uniqued, so we can compare pointers.
if (SrcSizes.size() != DstSizes.size() ||
!std::equal(SrcSizes.begin(), SrcSizes.end(), DstSizes.begin())) {
SrcSubscripts.clear();
@@ -3535,7 +3535,7 @@ bool DependenceInfo::tryDelinearizeFixedSize(
// iff the subscripts are positive and are less than the range of the
// dimension.
if (!DisableDelinearizationChecks) {
- auto AllIndicesInRange = [&](SmallVector<int, 4> &DimensionSizes,
+ auto AllIndicesInRange = [&](SmallVector<const SCEV *, 4> &DimensionSizes,
SmallVectorImpl<const SCEV *> &Subscripts,
Value *Ptr) {
size_t SSize = Subscripts.size();
@@ -3548,17 +3548,14 @@ bool DependenceInfo::tryDelinearizeFixedSize(
});
return false;
}
- if (auto *SType = dyn_cast<IntegerType>(S->getType())) {
- const SCEV *Range = SE->getConstant(
- ConstantInt::get(SType, DimensionSizes[I - 1], false));
- if (!isKnownLessThan(S, Range)) {
- LLVM_DEBUG({
- dbgs() << "Check failed: !isKnownLessThan(S, Range)\n";
- dbgs() << " S: " << *S << "\n"
- << " Range: " << *Range << "\n";
- });
- return false;
- }
+ const SCEV *Range = DimensionSizes[I - 1];
+ if (!isKnownLessThan(S, Range)) {
+ LLVM_DEBUG({
+ dbgs() << "Check failed: !isKnownLessThan(S, Range)\n";
+ dbgs() << " S: " << *S << "\n"
+ << " Range: " << *Range << "\n";
+ });
+ return false;
}
}
return true;
diff --git a/llvm/lib/Analysis/LoopCacheAnalysis.cpp b/llvm/lib/Analysis/LoopCacheAnalysis.cpp
index 050c32707596a..74bcce8f51a4c 100644
--- a/llvm/lib/Analysis/LoopCacheAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopCacheAnalysis.cpp
@@ -356,15 +356,14 @@ CacheCostTy IndexedReference::computeRefCost(const Loop &L,
bool IndexedReference::tryDelinearizeFixedSize(
const SCEV *AccessFn, SmallVectorImpl<const SCEV *> &Subscripts) {
- SmallVector<int, 4> ArraySizes;
+ SmallVector<const SCEV *, 4> ArraySizes;
if (!tryDelinearizeFixedSizeImpl(&SE, &StoreOrLoadInst, AccessFn, Subscripts,
ArraySizes))
return false;
// Populate Sizes with scev expressions to be used in calculations later.
for (auto Idx : seq<unsigned>(1, Subscripts.size()))
- Sizes.push_back(
- SE.getConstant(Subscripts[Idx]->getType(), ArraySizes[Idx - 1]));
+ Sizes.push_back(ArraySizes[Idx - 1]);
LLVM_DEBUG({
dbgs() << "Delinearized subscripts of fixed-size array\n"
diff --git a/polly/lib/Analysis/ScopBuilder.cpp b/polly/lib/Analysis/ScopBuilder.cpp
index 67a4c43455809..ec77b15ddd768 100644
--- a/polly/lib/Analysis/ScopBuilder.cpp
+++ b/polly/lib/Analysis/ScopBuilder.cpp
@@ -1463,7 +1463,7 @@ bool ScopBuilder::buildAccessMultiDimFixed(MemAccInst Inst, ScopStmt *Stmt) {
return false;
SmallVector<const SCEV *, 4> Subscripts;
- SmallVector<int, 4> Sizes;
+ SmallVector<const SCEV *, 4> Sizes;
getIndexExpressionsFromGEP(SE, GEP, Subscripts, Sizes);
auto *BasePtr = GEP->getOperand(0);
@@ -1475,8 +1475,6 @@ bool ScopBuilder::buildAccessMultiDimFixed(MemAccInst Inst, ScopStmt *Stmt) {
if (BasePtr != BasePointer->getValue())
return false;
- std::vector<const SCEV *> SizesSCEV;
-
const InvariantLoadsSetTy &ScopRIL = scop->getRequiredInvariantLoads();
Loop *SurroundingLoop = Stmt->getSurroundingLoop();
@@ -1494,11 +1492,9 @@ bool ScopBuilder::buildAccessMultiDimFixed(MemAccInst Inst, ScopStmt *Stmt) {
if (Sizes.empty())
return false;
+ std::vector<const SCEV *> SizesSCEV;
SizesSCEV.push_back(nullptr);
-
- for (auto V : Sizes)
- SizesSCEV.push_back(SE.getSCEV(
- ConstantInt::get(IntegerType::getInt64Ty(BasePtr->getContext()), V)));
+ SizesSCEV.insert(SizesSCEV.end(), Sizes.begin(), Sizes.end());
addArrayAccess(Stmt, Inst, AccType, BasePointer->getValue(), ElementType,
true, Subscripts, SizesSCEV, Val);
|
You can test this locally with the following command:git-clang-format --diff origin/main HEAD --extensions h,cpp -- llvm/include/llvm/Analysis/Delinearization.h llvm/lib/Analysis/Delinearization.cpp llvm/lib/Analysis/DependenceAnalysis.cpp llvm/lib/Analysis/LoopCacheAnalysis.cpp polly/lib/Analysis/ScopBuilder.cpp
View the diff from clang-format here.diff --git a/llvm/lib/Analysis/Delinearization.cpp b/llvm/lib/Analysis/Delinearization.cpp
index f438a9bd9..d2a300c8a 100644
--- a/llvm/lib/Analysis/Delinearization.cpp
+++ b/llvm/lib/Analysis/Delinearization.cpp
@@ -690,8 +690,8 @@ bool llvm::getIndexExpressionsFromGEP(ScalarEvolution &SE,
Subscripts.push_back(Expr);
if (!(DroppedFirstDim && i == 2))
- Sizes.push_back(SE.getConstant(Expr->getType(),
- ArrayTy->getNumElements()));
+ Sizes.push_back(
+ SE.getConstant(Expr->getType(), ArrayTy->getNumElements()));
Ty = ArrayTy->getElementType();
}
@@ -707,7 +707,8 @@ bool llvm::getIndexExpressionsFromGEP(ScalarEvolution &SE,
bool llvm::tryDelinearizeFixedSizeImpl(
ScalarEvolution *SE, Instruction *Inst, const SCEV *AccessFn,
- SmallVectorImpl<const SCEV *> &Subscripts, SmallVectorImpl<const SCEV *> &Sizes) {
+ SmallVectorImpl<const SCEV *> &Subscripts,
+ SmallVectorImpl<const SCEV *> &Sizes) {
Value *SrcPtr = getLoadStorePointerOperand(Inst);
// Check the simple case where the array dimensions are fixed size.
|
sebpop
requested review from
Meinersbur,
alexey-bataev,
kasuga-fj and
sjoerdmeijer
kasuga-fj
reviewed
Oct 14, 2025
Comment on lines
-1478
to
-1479
| std::vector<const SCEV *> SizesSCEV; | ||
|
|
There was a problem hiding this comment.
I don't think the declaration needs to be moved.
Comment on lines
+693
to
+694
| Sizes.push_back(SE.getConstant(Expr->getType(), | ||
| ArrayTy->getNumElements())); |
There was a problem hiding this comment.
Same as #156342 (comment), maybe using DataLayout::getIndexSize is better.
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clean up interface of getIndexExpressionsFromGEP to get SCEV expressions instead of int for Sizes of the arrays.
This intends to simplify the code in #156342 by avoiding conversions from SCEV to int and back to SCEV.