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[CIR] Upstream ArraySubscriptExpr from function parameter with pointer base #135493

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AmrDeveloper merged 2 commits into from
Apr 15, 2025
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[CIR] Upstream ArraySubscriptExpr from function parameter with pointer base #135493

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[CIR] Upstream ArraySubscriptExpr for base type as pointer
AmrDeveloper Apr 11, 2025
2bb03de
Address code review comments
AmrDeveloper Apr 14, 2025
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14 changes: 11 additions & 3 deletions clang/lib/CIR/CodeGen/CIRGenExpr.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -570,9 +570,17 @@ CIRGenFunction::emitArraySubscriptExpr(const clang::ArraySubscriptExpr *e) {
}

// The base must be a pointer; emit it with an estimate of its alignment.
cgm.errorNYI(e->getSourceRange(),
"emitArraySubscriptExpr: The base must be a pointer");
return {};
assert(e->getBase()->getType()->isPointerType() &&
"The base must be a pointer");

LValueBaseInfo eltBaseInfo;
const Address ptrAddr = emitPointerWithAlignment(e->getBase(), &eltBaseInfo);
// Propagate the alignment from the array itself to the result.
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@andykaylor andykaylor Apr 14, 2025

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What happened to the call to EmitIdxAfterBase()? It looks like you've simplified the code here (and in the earlier implementation), but I'm not sure we don't need some of what has been eliminated. At least when we add support for sanitizers we'll want the bounds check in emitIdxAfterBase.

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@AmrDeveloper AmrDeveloper Apr 14, 2025

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I think yes, I should keep it as lambda for the bounds checks in the future, I was thinking also of keeping it as a function but for now i will keep emitIdxAfterBase

const Address addxr = emitArraySubscriptPtr(
*this, cgm.getLoc(e->getBeginLoc()), cgm.getLoc(e->getEndLoc()), ptrAddr,
e->getType(), idx, cgm.getLoc(e->getExprLoc()),
/*shouldDecay=*/false);
return LValue::makeAddr(addxr, e->getType(), eltBaseInfo);
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@andykaylor andykaylor Apr 14, 2025

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You're missing an errorNYI here for ObjectC garbage collection. This should also happen for the case that returns on line 569 here but falls through in the incubator implementation.

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@AmrDeveloper AmrDeveloper Apr 14, 2025

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Done, I modified the lambda to just return the idx directly because no need to move the checks for RHS and LHS inside lambda

}

LValue CIRGenFunction::emitBinaryOperatorLValue(const BinaryOperator *e) {
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95 changes: 81 additions & 14 deletions clang/test/CIR/CodeGen/array.cpp
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Expand Up @@ -350,20 +350,87 @@ void func7() {
// OGCG: %[[ARR:.*]] = alloca [1 x ptr], align 8
// OGCG: call void @llvm.memset.p0.i64(ptr align 8 %[[ARR]], i8 0, i64 8, i1 false)

void func8(int p[10]) {}
// CIR: cir.func @func8(%arg0: !cir.ptr<!s32i>
// CIR: cir.alloca !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>, ["p", init]

// LLVM: define void @func8(ptr {{%.*}})
// LLVM-NEXT: alloca ptr, i64 1, align 8

// OGCG: alloca ptr, align 8
void func8(int arr[10]) {
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@andykaylor andykaylor Apr 14, 2025

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Can you add a test case where the parameter is a raw pointer. Something like this?

void func10(int *a) {
  int e = a[5];
}

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@AmrDeveloper AmrDeveloper Apr 14, 2025

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Done

int e = arr[0];
int e2 = arr[1];
}

void func9(int pp[10][5]) {}
// CIR: cir.func @func9(%arg0: !cir.ptr<!cir.array<!s32i x 5>>
// CIR: cir.alloca !cir.ptr<!cir.array<!s32i x 5>>, !cir.ptr<!cir.ptr<!cir.array<!s32i x 5>>>
// CIR: cir.func @func8(%[[ARG:.*]]: !cir.ptr<!s32i>
// CIR: %[[ARR:.*]] = cir.alloca !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>, ["arr", init]
// CIR: %[[INIT:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["e", init]
// CIR: %[[INIT_2:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["e2", init]
// CIR: cir.store %[[ARG]], %[[ARR]] : !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>
// CIR: %[[IDX:.*]] = cir.const #cir.int<0> : !s32i
// CIR: %[[TMP_1:.*]] = cir.load %[[ARR]] : !cir.ptr<!cir.ptr<!s32i>>, !cir.ptr<!s32i>
// CIR: %[[ELE_0:.*]] = cir.ptr_stride(%[[TMP_1]] : !cir.ptr<!s32i>, %[[IDX]] : !s32i), !cir.ptr<!s32i>
// CIR: %[[TMP_2:.*]] = cir.load %[[ELE_0]] : !cir.ptr<!s32i>, !s32i
// CIR: cir.store %[[TMP_2]], %[[INIT]] : !s32i, !cir.ptr<!s32i>
// CIR: %[[IDX_1:.*]] = cir.const #cir.int<1> : !s32i
// CIR: %[[TMP_3:.*]] = cir.load %[[ARR]] : !cir.ptr<!cir.ptr<!s32i>>, !cir.ptr<!s32i>
// CIR: %[[ELE_1:.*]] = cir.ptr_stride(%[[TMP_3]] : !cir.ptr<!s32i>, %[[IDX_1]] : !s32i), !cir.ptr<!s32i>
// CIR: %[[TMP_4:.*]] = cir.load %[[ELE_1]] : !cir.ptr<!s32i>, !s32i
// CIR: cir.store %[[TMP_4]], %[[INIT_2]] : !s32i, !cir.ptr<!s32i>

// LLVM: define void @func8(ptr %[[ARG:.*]])
// LLVM: %[[ARR:.*]] = alloca ptr, i64 1, align 8
// LLVM: %[[INIT:.*]] = alloca i32, i64 1, align 4
// LLVM: %[[INIT_2:.*]] = alloca i32, i64 1, align 4
// LLVM: store ptr %[[ARG]], ptr %[[ARR]], align 8
// LLVM: %[[TMP_1:.*]] = load ptr, ptr %[[ARR]], align 8
// LLVM: %[[ELE_0:.*]] = getelementptr i32, ptr %[[TMP_1]], i64 0
// LLVM: %[[TMP_2:.*]] = load i32, ptr %[[ELE_0]], align 4
// LLVM: store i32 %[[TMP_2]], ptr %[[INIT]], align 4
// LLVM: %[[TMP_3:.*]] = load ptr, ptr %[[ARR]], align 8
// LLVM: %[[ELE_1:.*]] = getelementptr i32, ptr %[[TMP_3]], i64 1
// LLVM: %[[TMP_4:.*]] = load i32, ptr %[[ELE_1]], align 4
// LLVM: store i32 %[[TMP_4]], ptr %[[INIT_2]], align 4

// OGCG: %[[ARR:.*]] = alloca ptr, align 8
// OGCG: %[[INIT:.*]] = alloca i32, align 4
// OGCG: %[[INIT_2:.*]] = alloca i32, align 4
// OGCG: store ptr {{%.*}}, ptr %[[ARR]], align 8
// OGCG: %[[TMP_1:.*]] = load ptr, ptr %[[ARR]], align 8
// OGCG: %[[ELE_0:.*]] = getelementptr inbounds i32, ptr %[[TMP_1]], i64 0
// OGCG: %[[TMP_2:.*]] = load i32, ptr %[[ELE_0]], align 4
// OGCG: store i32 %[[TMP_2]], ptr %[[INIT]], align 4
// OGCG: %[[TMP_3:.*]] = load ptr, ptr %[[ARR]], align 8
// OGCG: %[[ELE_1:.*]] = getelementptr inbounds i32, ptr %[[TMP_3]], i64 1
// OGCG: %[[TMP_2:.*]] = load i32, ptr %[[ELE_1]], align 4
// OGCG: store i32 %[[TMP_2]], ptr %[[INIT_2]], align 4

// LLVM: define void @func9(ptr {{%.*}})
// LLVM-NEXT: alloca ptr, i64 1, align 8
void func9(int arr[10][5]) {
int e = arr[1][2];
}

// OGCG: alloca ptr, align 8
// CIR: cir.func @func9(%[[ARG:.*]]: !cir.ptr<!cir.array<!s32i x 5>>
// CIR: %[[ARR:.*]] = cir.alloca !cir.ptr<!cir.array<!s32i x 5>>, !cir.ptr<!cir.ptr<!cir.array<!s32i x 5>>>, ["arr", init]
// CIR: %[[INIT:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["e", init]
// CIR: cir.store %[[ARG]], %[[ARR]] : !cir.ptr<!cir.array<!s32i x 5>>, !cir.ptr<!cir.ptr<!cir.array<!s32i x 5>>>
// CIR: %[[IDX:.*]] = cir.const #cir.int<2> : !s32i
// CIR: %[[IDX_1:.*]] = cir.const #cir.int<1> : !s32i
// CIR: %[[TMP_1:.*]] = cir.load %[[ARR]] : !cir.ptr<!cir.ptr<!cir.array<!s32i x 5>>>, !cir.ptr<!cir.array<!s32i x 5>>
// CIR: %[[ARR_1:.*]] = cir.ptr_stride(%[[TMP_1]] : !cir.ptr<!cir.array<!s32i x 5>>, %[[IDX_1]] : !s32i), !cir.ptr<!cir.array<!s32i x 5>>
// CIR: %[[ARR_1_PTR:.*]] = cir.cast(array_to_ptrdecay, %[[ARR_1]] : !cir.ptr<!cir.array<!s32i x 5>>), !cir.ptr<!s32i>
// CIR: %[[ARR_1_2:.*]] = cir.ptr_stride(%[[ARR_1_PTR]] : !cir.ptr<!s32i>, %[[IDX]] : !s32i), !cir.ptr<!s32i>
// CIR: %[[TMP_2:.*]] = cir.load %[[ARR_1_2]] : !cir.ptr<!s32i>, !s32i
// CIR: cir.store %[[TMP_2]], %[[INIT]] : !s32i, !cir.ptr<!s32i>

// LLVM: define void @func9(ptr %[[ARG:.*]])
// LLVM: %[[ARR:.*]] = alloca ptr, i64 1, align 8
// LLVM: %[[INIT:.*]] = alloca i32, i64 1, align 4
// LLVM: store ptr %[[ARG]], ptr %[[ARR]], align 8
// LLVM: %[[TMP_1:.*]] = load ptr, ptr %[[ARR]], align 8
// LLVM: %[[ARR_1:.*]] = getelementptr [5 x i32], ptr %[[TMP_1]], i64 1
// LLVM: %[[ARR_1_PTR:.*]] = getelementptr i32, ptr %[[ARR_1]], i32 0
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@andykaylor andykaylor Apr 14, 2025

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This is not related to the current PR, but it's unfortunate that we're generating a getelementptr for the array_to_ptrdecay cast. That seems entirely unnecessary.

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@bcardosolopes bcardosolopes Apr 14, 2025

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Yea, seems like lowering could be slightly smarter and fold this right away

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@AmrDeveloper AmrDeveloper Apr 14, 2025

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Yes, I can take a look and handle it in other PR

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@bcardosolopes bcardosolopes Apr 14, 2025

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You might need to change similar in the incubator

// LLVM: %[[ARR_1_2:.*]] = getelementptr i32, ptr %[[ARR_1_PTR]], i64 2
// LLVM: %[[TMP_2:.*]] = load i32, ptr %[[ARR_1_2]], align 4
// LLVM: store i32 %[[TMP_2]], ptr %[[INIT]], align 4

// OGCG: %[[ARR:.*]] = alloca ptr, align 8
// OGCG: %[[INIT:.*]] = alloca i32, align 4
// OGCG: store ptr {{%.*}}, ptr %[[ARR]], align 8
// OGCG: %[[TMP_1:.*]] = load ptr, ptr %[[ARR]], align 8
// OGCG: %[[ARR_1:.*]] = getelementptr inbounds [5 x i32], ptr %[[TMP_1]], i64 1
// OGCG: %[[ARR_1_2:.*]] = getelementptr inbounds [5 x i32], ptr %[[ARR_1]], i64 0, i64 2
// OGCG: %[[TMP_2:.*]] = load i32, ptr %[[ARR_1_2]], align 4
// OGCG: store i32 %[[TMP_2]], ptr %[[INIT]], align 4