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[Attributor] Check range size before constant fold load #151359

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Merged
merged 2 commits into from
Oct 25, 2025
Merged

[Attributor] Check range size before constant fold load #151359

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c6a3ff2
[Attributor] Check range size before constant fold load
shiltian Oct 15, 2025
003c4a9
add extra test
shiltian Oct 24, 2025
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3 changes: 3 additions & 0 deletions llvm/lib/Transforms/IPO/Attributor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -272,6 +272,9 @@ AA::getInitialValueForObj(Attributor &A, const AbstractAttribute &QueryingAA,
}

if (RangePtr && !RangePtr->offsetOrSizeAreUnknown()) {
int64_t StorageSize = DL.getTypeStoreSize(&Ty);
if (StorageSize != RangePtr->Size)
return nullptr;
APInt Offset = APInt(64, RangePtr->Offset);
return ConstantFoldLoadFromConst(Initializer, &Ty, Offset, DL);
}
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38 changes: 38 additions & 0 deletions llvm/test/Transforms/Attributor/range-and-constant-fold.ll
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@@ -0,0 +1,38 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
; RUN: opt -S -passes=attributor %s -o - | FileCheck %s

@g = internal unnamed_addr addrspace(4) constant [3 x i8] c"12\00", align 16

define void @foo(i32 %a, i32 %b, ptr %p.0, ptr %p.1) {
; CHECK-LABEL: define void @foo(
; CHECK-SAME: i32 [[A:%.*]], i32 [[B:%.*]], ptr nofree nonnull writeonly captures(none) dereferenceable(1) [[P_0:%.*]], ptr nofree nonnull writeonly align 4 captures(none) dereferenceable(8) [[P_1:%.*]]) #[[ATTR0:[0-9]+]] {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[A]], [[B]]
; CHECK-NEXT: br i1 [[CMP]], label %[[L1:.*]], label %[[L2:.*]]
; CHECK: [[L1]]:
; CHECK-NEXT: br label %[[L3:.*]]
; CHECK: [[L2]]:
; CHECK-NEXT: br label %[[L3]]
; CHECK: [[L3]]:
; CHECK-NEXT: [[PHI:%.*]] = phi ptr addrspace(4) [ @g, %[[L1]] ], [ getelementptr inbounds nuw (i8, ptr addrspace(4) @g, i64 1), %[[L2]] ]
; CHECK-NEXT: [[LOAD_SMALL:%.*]] = load i8, ptr addrspace(4) [[PHI]], align 4
; CHECK-NEXT: store i8 [[LOAD_SMALL]], ptr [[P_0]], align 1
; CHECK-NEXT: [[LOAD_LARGE:%.*]] = load i64, ptr addrspace(4) [[PHI]], align 4
; CHECK-NEXT: store i64 [[LOAD_LARGE]], ptr [[P_1]], align 4
; CHECK-NEXT: ret void
;
entry:
%cmp = icmp ne i32 %a, %b
br i1 %cmp, label %l1, label %l2
l1:
br label %l3
l2:
br label %l3
l3:
%phi = phi ptr addrspace(4) [ @g, %l1 ], [ getelementptr inbounds nuw (i8, ptr addrspace(4) @g, i64 1), %l2 ]
%load.small = load i8, ptr addrspace(4) %phi
store i8 %load.small, ptr %p.0
%load.large = load i64, ptr addrspace(4) %phi
store i64 %load.large, ptr %p.1
ret void
}