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Merged
kasuga-fj merged 5 commits into from
Oct 30, 2025
Merged

[DA] Add tests where dependencies are missed due to overflow (NFC) #164246

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16601d9
[DA] Add tests where dependencies are missed due to overflow
kasuga-fj Oct 17, 2025
7444b19
use --check-prefixes
kasuga-fj Oct 28, 2025
ae260d3
address review comments
kasuga-fj Oct 29, 2025
314ad42
fix typo
kasuga-fj Oct 29, 2025
013fdde
Merge branch 'main' into users/kasuga-fj/da-add-tests-for-overflow
kasuga-fj Oct 30, 2025
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66 changes: 66 additions & 0 deletions llvm/test/Analysis/DependenceAnalysis/gcd-miv-overflow.ll
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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-ALL
; RUN: opt < %s -disable-output "-passes=print<da>" -da-enable-dependence-test=gcd-miv 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-GCD-MIV

; offset0 = 4;
; offset1 = 0;
; for (i = 0; i < 100; i++) {
; A[offset0] = 1;
; A[offset1] = 2;
; offset0 += 3*m;
; offset1 += 3;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist. E.g., consider `m` is 12297829382473034411, which
; is a modular multiplicative inverse of 3 under modulo 2^64. Then `offset0` is
; effectively `i + 4`, so accesses will be as follows:
;
; - A[offset0] : A[4], A[5], A[6], ...
; - A[offset1] : A[0], A[3], A[6], ...
;
; The root cause is that DA assumes `3*m` begin a multiple of 3 in mathematical
; sense, which isn't necessarily true due to overflow.
;
define void @gcdmiv_coef_ovfl(ptr %A, i64 %m) {
Comment on lines 7 to 27
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@kasuga-fj kasuga-fj Oct 21, 2025

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This is a bit special; the coefficient have already wrapped. This should be fixed by #164408 .

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@Meinersbur Meinersbur Oct 28, 2025 •
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3*m is loop-invariant, and even computed before the loop. Ideally, DA shouldn't care about overflow, it us just "some invariant value" with this same result if only %step was passed as argument directly instead of %m.

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@kasuga-fj kasuga-fj Oct 29, 2025

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I strongly agree with that, and I feel like the situation may be more serious. For example, given two accesses A[i + b 2*%n] and A[i + %n], StrongSIV regards the distance between them (i.e., Delta in strongSIVtest) as 2*%n - %n = %n. I think this is only valid if 2*%n doesn't overflow.

I think similar issues would exist in other parts of DA as well (StrongSIV and SymbolicRDIV are suspicious).

; CHECK-ALL-LABEL: 'gcdmiv_coef_ovfl'
; CHECK-ALL-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
;
; CHECK-GCD-MIV-LABEL: 'gcdmiv_coef_ovfl'
; CHECK-GCD-MIV-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-GCD-MIV-NEXT: da analyze - consistent output [*]!
; CHECK-GCD-MIV-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-GCD-MIV-NEXT: da analyze - none!
; CHECK-GCD-MIV-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-GCD-MIV-NEXT: da analyze - consistent output [*]!
;
entry:
%step = mul i64 3, %m
br label %loop

loop:
%i = phi i64 [ 0, %entry ], [ %i.inc, %loop ]
%offset.0 = phi i64 [ 4, %entry ] , [ %offset.0.next, %loop ]
%offset.1 = phi i64 [ 0, %entry ] , [ %offset.1.next, %loop ]
%gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset.0
%gep.1 = getelementptr inbounds i8, ptr %A, i64 %offset.1
store i8 1, ptr %gep.0
store i8 2, ptr %gep.1
%i.inc = add nuw nsw i64 %i, 1
%offset.0.next = add nsw i64 %offset.0, %step
%offset.1.next = add nsw i64 %offset.1, 3
%ec = icmp eq i64 %i.inc, 100
br i1 %ec, label %exit, label %loop

exit:
ret void
}
;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
; CHECK: {{.*}}
68 changes: 68 additions & 0 deletions llvm/test/Analysis/DependenceAnalysis/strong-siv-overflow.ll
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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-ALL
; RUN: opt < %s -disable-output "-passes=print<da>" -da-enable-dependence-test=strong-siv 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-STRONG-SIV

; offset0 = -2;
; offset1 = -4;
; for (i = 0; i < (1LL << 62); i++, offset0 += 2, offset1 += 2) {
; if (0 <= offset0)
; A[offset0] = 1;
; if (0 <= offset1)
; A[offset1] = 2;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist.
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Do you know at which values of i, offset0 and offset1?

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@kasuga-fj kasuga-fj Oct 29, 2025

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I thought the dependency in this case is trivial, but using offset0 and offset1 makes it unclear. I've rewritten the pseudo code and add brief comments to clarify the dependency.

; The root cause is that the product of the BTC and the coefficient triggers an
; overflow.
define void @strongsiv_const_ovfl(ptr %A) {
; CHECK-LABEL: 'strongsiv_const_ovfl'
; CHECK-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-NEXT: da analyze - none!
; CHECK-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-NEXT: da analyze - none!
; CHECK-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-NEXT: da analyze - none!
;
entry:
br label %loop.header

loop.header:
%i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
%offset.0 = phi i64 [ -2, %entry ], [ %offset.0.next, %loop.latch ]
%offset.1 = phi i64 [ -4, %entry ], [ %offset.1.next, %loop.latch ]
%ec = icmp eq i64 %i, 4611686018427387904
br i1 %ec, label %exit, label %loop.body

loop.body:
%cond.0 = icmp sge i64 %offset.0, 0
%cond.1 = icmp sge i64 %offset.1, 0
br i1 %cond.0, label %if.then.0, label %loop.middle

if.then.0:
%gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset.0
store i8 1, ptr %gep.0
br label %loop.middle

loop.middle:
br i1 %cond.1, label %if.then.1, label %loop.latch

if.then.1:
%gep.1 = getelementptr inbounds i8, ptr %A, i64 %offset.1
store i8 2, ptr %gep.1
br label %loop.latch

loop.latch:
%i.inc = add nuw nsw i64 %i, 1
%offset.0.next = add nsw i64 %offset.0, 2
%offset.1.next = add nsw i64 %offset.1, 2
br label %loop.header

exit:
ret void
}
;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
; CHECK-ALL: {{.*}}
; CHECK-STRONG-SIV: {{.*}}
131 changes: 131 additions & 0 deletions llvm/test/Analysis/DependenceAnalysis/symbolic-rdiv-overflow.ll
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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-ALL
; RUN: opt < %s -disable-output "-passes=print<da>" -da-enable-dependence-test=symbolic-rdiv 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-SYMBOLIC-RDIV

; offset = -2;
; for (i = 0; i < (1LL << 62); i++, offset += 2) {
; if (0 <= offset0)
; A[offset0] = 1;
; A[i] = 2;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist.
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@Meinersbur Meinersbur Oct 28, 2025

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Do you know at which values of i and offset0?

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@kasuga-fj kasuga-fj Oct 29, 2025

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Revised the pseudo code and added brief comment.

; The root cause is that the product of the BTC and the coefficient triggers an
; overflow.
define void @symbolicrdiv_prod_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'symbolicrdiv_prod_ovfl'
; CHECK-ALL-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
;
; CHECK-SYMBOLIC-RDIV-LABEL: 'symbolicrdiv_prod_ovfl'
; CHECK-SYMBOLIC-RDIV-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-SYMBOLIC-RDIV-NEXT: da analyze - none!
; CHECK-SYMBOLIC-RDIV-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT: da analyze - none!
; CHECK-SYMBOLIC-RDIV-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT: da analyze - consistent output [*]!
;
entry:
br label %loop.header

loop.header:
%i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
%offset = phi i64 [ -2, %entry ], [ %offset.next, %loop.latch ]
%ec = icmp eq i64 %i, 4611686018427387904
br i1 %ec, label %exit, label %loop.body

loop.body:
%cond = icmp sge i64 %offset, 0
br i1 %cond, label %if.then, label %loop.latch

if.then:
%gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset
store i8 1, ptr %gep.0
br label %loop.latch

loop.latch:
%gep.1 = getelementptr inbounds i8, ptr %A, i64 %i
store i8 2, ptr %gep.1
%i.inc = add nuw nsw i64 %i, 1
%offset.next = add nsw i64 %offset, 2
br label %loop.header

exit:
ret void
}

; offset0 = -4611686018427387904 // -2^62
; offset1 = 4611686018427387904 // 2^62
; for (i = 0; i < (1LL << 62) - 100; i++) {
; if (0 <= offset0)
; A[offset0] = 1;
; if (0 <= offset1)
; A[offset1] = 2;
; offset0 += 2;
; offset1 -= 1;
; }
;
; FIXME: DependenceAnalysis currently detects no dependency between the two
; stores, but it does exist.
; The root cause is that the calculation of the differenct between the two
; constants (-2^62 and 2^62) triggers an overflow.
define void @symbolicrdiv_delta_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'symbolicrdiv_delta_ovfl'
; CHECK-ALL-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
;
; CHECK-SYMBOLIC-RDIV-LABEL: 'symbolicrdiv_delta_ovfl'
; CHECK-SYMBOLIC-RDIV-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 1, ptr %gep.0, align 1
; CHECK-SYMBOLIC-RDIV-NEXT: da analyze - consistent output [*]!
; CHECK-SYMBOLIC-RDIV-NEXT: Src: store i8 1, ptr %gep.0, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT: da analyze - none!
; CHECK-SYMBOLIC-RDIV-NEXT: Src: store i8 2, ptr %gep.1, align 1 --> Dst: store i8 2, ptr %gep.1, align 1
; CHECK-SYMBOLIC-RDIV-NEXT: da analyze - consistent output [*]!
;
entry:
br label %loop.header

loop.header:
%i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
%offset.0 = phi i64 [ -4611686018427387904, %entry ], [ %offset.0.next, %loop.latch ]
%offset.1 = phi i64 [ 4611686018427387904, %entry ], [ %offset.1.next, %loop.latch ]
%cond.0 = icmp sge i64 %offset.0, 0
%cond.1 = icmp sge i64 %offset.1, 0
br i1 %cond.0, label %if.then.0, label %loop.middle

if.then.0:
%gep.0 = getelementptr inbounds i8, ptr %A, i64 %offset.0
store i8 1, ptr %gep.0
br label %loop.middle

loop.middle:
br i1 %cond.1, label %if.then.1, label %loop.latch

if.then.1:
%gep.1 = getelementptr inbounds i8, ptr %A, i64 %offset.1
store i8 2, ptr %gep.1
br label %loop.latch

loop.latch:
%i.inc = add nuw nsw i64 %i, 1
%offset.0.next = add nsw i64 %offset.0, 2
%offset.1.next = sub nsw i64 %offset.1, 1
%ec = icmp eq i64 %i.inc, 4611686018427387804 ; 2^62 - 100
br i1 %ec, label %exit, label %loop.header

exit:
ret void
}
;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
; CHECK: {{.*}}
125 changes: 125 additions & 0 deletions llvm/test/Analysis/DependenceAnalysis/weak-crossing-siv-overflow.ll
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; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 6
; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-ALL
; RUN: opt < %s -disable-output "-passes=print<da>" -da-enable-dependence-test=weak-crossing-siv 2>&1 \
; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-WEAK-CROSSING-SIV

; max_i = INT64_MAX/3 // 3074457345618258602
; for (long long i = 0; i <= max_i; i++) {
; A[-3*i + INT64_MAX] = 0;
; if (i)
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@Meinersbur Meinersbur Oct 28, 2025

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Does the if (i) matter for DA?

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@kasuga-fj kasuga-fj Oct 29, 2025

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The purpose of this condition (and similar ones in other cases) is to avoid UB caused by the combination of the size limitation of allocated objects and inbounds. However, I'm not sure if the presence of these branches affects DA, or simply dropping inbounds would be sufficient.

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I've seen it in the other cases to avoid the subscripts becoming negative. In this case, A[-3*0 + INT64_MAX] == A[INT64_MAX] still seems to be valid, at least no less than other values of i. E.g. with &A == nullptr (valid in Linux kernel code), the resulting address is still within the half-address space bound.

However, I see the point, we can/should leave it to be on the safe side.

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@kasuga-fj kasuga-fj Oct 30, 2025

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This is if (i) A[3*i - 2], which prevents access A[3*0 - 2] == A[-2]. Like the other guards, this one also excludes negative subscripts.

; A[3*i - 2] = 1;
; }
;
; FIXME: DependencyAnalsysis currently detects no dependency between
; `A[-3*i + INT64_MAX]` and `A[3*i - 2]`, but it does exist. For example,
;
; memory location | -3*i + INT64_MAX | 3*i - 2
; ------------------|------------------|-----------
; A[1] | i = max_i | i = 1
; A[INT64_MAX - 3] | i = 1 | i = max_i
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Suggested change
; memory location | -3*i + INT64_MAX | 3*i - 2
; ------------------|------------------|-----------
; A[1] | i = max_i | i = 1
; A[INT64_MAX - 3] | i = 1 | i = max_i
; memory access | i == 1 | i == max_i
; ---------------------|------------------|-----------
; A[-3*i + INT64_MAX] | A[INT64_MAX - 3] | A[1]
; A[3*i - 2] | A[1] | A[INT64_MAX - 3]

It is not clear that the columns represent the memory access at line 9, respectively at line 11.
I find a table with location addresses per values of i for each memory access more intiuitive than a table per address and when it is accessed.

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Thanks, replace the table. Also added similar one to other non-trivial cases.

;
; The root cause is that the calculation of the differenct between the two
; constants (INT64_MAX and -2) triggers an overflow.

define void @weakcorssing_delta_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'weakcorssing_delta_ovfl'
; CHECK-ALL-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 0, ptr %idx.0, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 1, ptr %idx.1, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
;
; CHECK-WEAK-CROSSING-SIV-LABEL: 'weakcorssing_delta_ovfl'
; CHECK-WEAK-CROSSING-SIV-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 0, ptr %idx.0, align 1
; CHECK-WEAK-CROSSING-SIV-NEXT: da analyze - consistent output [*]!
; CHECK-WEAK-CROSSING-SIV-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-WEAK-CROSSING-SIV-NEXT: da analyze - none!
; CHECK-WEAK-CROSSING-SIV-NEXT: Src: store i8 1, ptr %idx.1, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-WEAK-CROSSING-SIV-NEXT: da analyze - consistent output [*]!
;
entry:
br label %loop.header

loop.header:
%i = phi i64 [ 0, %entry ], [ %i.inc, %loop.latch ]
%subscript.0 = phi i64 [ 9223372036854775807, %entry ], [ %subscript.0.next, %loop.latch ]
%subscript.1 = phi i64 [ -2, %entry ], [ %subscript.1.next, %loop.latch ]
%idx.0 = getelementptr inbounds i8, ptr %A, i64 %subscript.0
store i8 0, ptr %idx.0
%cond.store = icmp ne i64 %i, 0
br i1 %cond.store, label %if.store, label %loop.latch

if.store:
%idx.1 = getelementptr inbounds i8, ptr %A, i64 %subscript.1
store i8 1, ptr %idx.1
br label %loop.latch

loop.latch:
%i.inc = add nuw nsw i64 %i, 1
%subscript.0.next = add nsw i64 %subscript.0, -3
%subscript.1.next = add nsw i64 %subscript.1, 3
%ec = icmp sgt i64 %i.inc, 3074457345618258602
br i1 %ec, label %exit, label %loop.header

exit:
ret void
}

; max_i = INT64_MAX/3 // 3074457345618258602
; for (long long i = 0; i <= max_i; i++) {
; A[-3*i + INT64_MAX] = 0;
; A[3*i + 1] = 1;
; }
;
; FIXME: DependencyAnalsysis currently detects no dependency between
; `A[-3*i + INT64_MAX]` and `A[3*i - 2]`, but it does exist. For example,
;
; memory location | -3*i + INT64_MAX | 3*i + 1
; ------------------|------------------|--------------
; A[1] | i = max_i | i = 0
; A[INT64_MAX - 3] | i = 1 | i = max_i - 1
;
; The root cause is that the product of the BTC, the coefficient, and 2
; triggers an overflow.
;
define void @weakcorssing_prod_ovfl(ptr %A) {
; CHECK-ALL-LABEL: 'weakcorssing_prod_ovfl'
; CHECK-ALL-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 0, ptr %idx.0, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
; CHECK-ALL-NEXT: Src: store i8 1, ptr %idx.1, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-ALL-NEXT: da analyze - none!
;
; CHECK-WEAK-CROSSING-SIV-LABEL: 'weakcorssing_prod_ovfl'
; CHECK-WEAK-CROSSING-SIV-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 0, ptr %idx.0, align 1
; CHECK-WEAK-CROSSING-SIV-NEXT: da analyze - consistent output [*]!
; CHECK-WEAK-CROSSING-SIV-NEXT: Src: store i8 0, ptr %idx.0, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-WEAK-CROSSING-SIV-NEXT: da analyze - none!
; CHECK-WEAK-CROSSING-SIV-NEXT: Src: store i8 1, ptr %idx.1, align 1 --> Dst: store i8 1, ptr %idx.1, align 1
; CHECK-WEAK-CROSSING-SIV-NEXT: da analyze - consistent output [*]!
;
entry:
br label %loop

loop:
%i = phi i64 [ 0, %entry ], [ %i.inc, %loop ]
%subscript.0 = phi i64 [ 9223372036854775807, %entry ], [ %subscript.0.next, %loop ]
%subscript.1 = phi i64 [ 1, %entry ], [ %subscript.1.next, %loop ]
%idx.0 = getelementptr inbounds i8, ptr %A, i64 %subscript.0
%idx.1 = getelementptr inbounds i8, ptr %A, i64 %subscript.1
store i8 0, ptr %idx.0
store i8 1, ptr %idx.1
%i.inc = add nuw nsw i64 %i, 1
%subscript.0.next = add nsw i64 %subscript.0, -3
%subscript.1.next = add nsw i64 %subscript.1, 3
%ec = icmp sgt i64 %i.inc, 3074457345618258602
br i1 %ec, label %exit, label %loop

exit:
ret void
}
;; NOTE: These prefixes are unused and the list is autogenerated. Do not add tests below this line:
; CHECK: {{.*}}
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