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[SeparateConstOffsetFromGEP] Support multiple indices in reorderGEP #92339

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Merged
merged 2 commits into from
May 21, 2024
Merged

[SeparateConstOffsetFromGEP] Support multiple indices in reorderGEP #92339

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1a7351e
[SeparateConstOffsetFromGEP] Support multiple indices in reorderGEP
nikic May 16, 2024
3e13706
explicit lambda capture
nikic May 21, 2024
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19 changes: 6 additions & 13 deletions llvm/lib/Transforms/Scalar/SeparateConstOffsetFromGEP.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -972,14 +972,9 @@ SeparateConstOffsetFromGEP::lowerToArithmetics(GetElementPtrInst *Variadic,

bool SeparateConstOffsetFromGEP::reorderGEP(GetElementPtrInst *GEP,
TargetTransformInfo &TTI) {
if (GEP->getNumIndices() != 1)
return false;

auto PtrGEP = dyn_cast<GetElementPtrInst>(GEP->getPointerOperand());
if (!PtrGEP)
return false;
if (PtrGEP->getNumIndices() != 1)
return false;

bool NestedNeedsExtraction;
int64_t NestedByteOffset =
Expand All @@ -997,14 +992,12 @@ bool SeparateConstOffsetFromGEP::reorderGEP(GetElementPtrInst *GEP,
bool PtrGEPInBounds = PtrGEP->isInBounds();
bool IsChainInBounds = GEPInBounds && PtrGEPInBounds;
if (IsChainInBounds) {
auto GEPIdx = GEP->indices().begin();
auto KnownGEPIdx = computeKnownBits(GEPIdx->get(), *DL);
IsChainInBounds &= KnownGEPIdx.isNonNegative();
if (IsChainInBounds) {
auto PtrGEPIdx = PtrGEP->indices().begin();
auto KnownPtrGEPIdx = computeKnownBits(PtrGEPIdx->get(), *DL);
IsChainInBounds &= KnownPtrGEPIdx.isNonNegative();
}
auto IsKnownNonNegative = [this](Value *V) {
return isKnownNonNegative(V, *DL);
};
IsChainInBounds &= all_of(GEP->indices(), IsKnownNonNegative);
if (IsChainInBounds)
IsChainInBounds &= all_of(PtrGEP->indices(), IsKnownNonNegative);
Comment on lines +998 to +1000
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Does this work? I'm never sure how flexible concat is.

Suggested change
IsChainInBounds &= all_of(GEP->indices(), IsKnownNonNegative);
if (IsChainInBounds)
IsChainInBounds &= all_of(PtrGEP->indices(), IsKnownNonNegative);
IsChainInBounds &= all_of(concat(GEP->indices(), PtrGEP->indices()), IsKnownNonNegative);

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That doesn't work, and I couldn't figure out how to make it to work.

}

IRBuilder<> Builder(GEP);
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8 changes: 4 additions & 4 deletions llvm/test/Transforms/SeparateConstOffsetFromGEP/AMDGPU/reorder-gep.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -288,8 +288,8 @@ entry:
define void @multiple_index_maybe_neg(ptr %in.ptr, i64 %in.idx1) {
; CHECK-LABEL: define void @multiple_index_maybe_neg(
; CHECK-SAME: ptr [[IN_PTR:%.*]], i64 [[IN_IDX1:%.*]]) #[[ATTR0]] {
; CHECK-NEXT: [[CONST1:%.*]] = getelementptr inbounds [2 x <2 x i8>], ptr [[IN_PTR]], i64 0, i64 1
; CHECK-NEXT: [[IDX1:%.*]] = getelementptr inbounds [2 x <2 x i8>], ptr [[CONST1]], i64 0, i64 [[IN_IDX1]]
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr [2 x <2 x i8>], ptr [[IN_PTR]], i64 0, i64 [[IN_IDX1]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr [2 x <2 x i8>], ptr [[TMP1]], i64 0, i64 1
; CHECK-NEXT: ret void
;
%const1 = getelementptr inbounds [2 x <2 x i8>], ptr %in.ptr, i64 0, i64 1
Expand All @@ -301,8 +301,8 @@ define void @multiple_index_nonneg(ptr %in.ptr, i64 %in.idx1) {
; CHECK-LABEL: define void @multiple_index_nonneg(
; CHECK-SAME: ptr [[IN_PTR:%.*]], i64 [[IN_IDX1:%.*]]) #[[ATTR0]] {
; CHECK-NEXT: [[IN_IDX1_NNEG:%.*]] = and i64 [[IN_IDX1]], 9223372036854775807
; CHECK-NEXT: [[CONST1:%.*]] = getelementptr inbounds [2 x <2 x i8>], ptr [[IN_PTR]], i64 0, i64 1
; CHECK-NEXT: [[IDX1:%.*]] = getelementptr inbounds [2 x <2 x i8>], ptr [[CONST1]], i64 0, i64 [[IN_IDX1_NNEG]]
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds [2 x <2 x i8>], ptr [[IN_PTR]], i64 0, i64 [[IN_IDX1_NNEG]]
; CHECK-NEXT: [[TMP2:%.*]] = getelementptr inbounds [2 x <2 x i8>], ptr [[TMP1]], i64 0, i64 1
; CHECK-NEXT: ret void
;
%in.idx1.nneg = and i64 %in.idx1, 9223372036854775807
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