[llvm] [DA] Add test for the Exact test misses dependency due to overflow (PR #200780)

[Ryotaro Kasuga via llvm-commits]

https://github.com/kasuga-fj created https://github.com/llvm/llvm-project/pull/200780

None

>From 78724036520840dd6d0649e8ef909398b9d6c0b0 Mon Sep 17 00:00:00 2001
From: Ryotaro Kasuga <kasuga.ryotaro at fujitsu.com>
Date: Mon, 1 Jun 2026 10:16:07 +0000
Subject: [PATCH] [DA] Add test for the Exact test misses dependency due to
 overflow

---
 .../exact-siv-mul-overflow.ll                 | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 llvm/test/Analysis/DependenceAnalysis/exact-siv-mul-overflow.ll

diff --git a/llvm/test/Analysis/DependenceAnalysis/exact-siv-mul-overflow.ll b/llvm/test/Analysis/DependenceAnalysis/exact-siv-mul-overflow.ll
new file mode 100644
index 0000000000000..92e1f9ac565fd
--- /dev/null
+++ b/llvm/test/Analysis/DependenceAnalysis/exact-siv-mul-overflow.ll
@@ -0,0 +1,54 @@
+; 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=exact-siv 2>&1 \
+; RUN:     | FileCheck %s --check-prefixes=CHECK,CHECK-EXACT-SIV
+
+target datalayout = "e-m:e-p:32:32-i64:64-n32-S128"
+
+; for (i = 0; i < 160000000; i++) {
+;   A[5*i] = 0;
+;   A[8*i + 750000000] = 1;
+; }
+;
+; There is a dependency between the two accesses, for example,
+;
+;  memory access     | i = 0         | i = 150000000
+; -------------------|---------------|---------------
+;  A[5*i]            |               | A[750000000]
+;  A[8*i + 750000000]| A[750000000]  |
+;
+; FIXME: DependenceAnalysis currently fails to detect this dependency due to
+; mishandling of overflow.
+;
+define void @exactsiv_mul_overflow(ptr %A) {
+; CHECK-LABEL: 'exactsiv_mul_overflow'
+; CHECK-NEXT:  Src: store i8 0, ptr %src.ptr, align 1 --> Dst: store i8 0, ptr %src.ptr, align 1
+; CHECK-NEXT:    da analyze - none!
+; CHECK-NEXT:  Src: store i8 0, ptr %src.ptr, align 1 --> Dst: store i8 1, ptr %dst.ptr, align 1
+; CHECK-NEXT:    da analyze - none!
+; CHECK-NEXT:  Src: store i8 1, ptr %dst.ptr, align 1 --> Dst: store i8 1, ptr %dst.ptr, align 1
+; CHECK-NEXT:    da analyze - none!
+;
+entry:
+  br label %loop
+
+loop:
+  %i = phi i32 [ 0, %entry ], [ %i.next, %loop ]
+  %src.idx = mul nsw i32 %i, 5
+  %src.ptr = getelementptr inbounds i8, ptr %A, i32 %src.idx
+  store i8 0, ptr %src.ptr
+  %dst.idx.1 = mul nsw i32 %i, 8
+  %dst.idx = add nsw i32 %dst.idx.1, 750000000
+  %dst.ptr = getelementptr inbounds i8, ptr %A, i32 %dst.idx
+  store i8 1, ptr %dst.ptr
+  %i.next = add nsw i32 %i, 1
+  %ec = icmp eq i32 %i.next, 160000000
+  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-ALL: {{.*}}
+; CHECK-EXACT-SIV: {{.*}}