[llvm] [DependenceAnalysis] Prevent non-AddRec expressions from reaching testSIV (PR #154980)
Sebastian Pop via llvm-commits
llvm-commits at lists.llvm.org
Tue Nov 25 12:57:54 PST 2025
https://github.com/sebpop updated https://github.com/llvm/llvm-project/pull/154980
>From 0ae1000a9b86f4b253a6eced860420c89ebaaf8c Mon Sep 17 00:00:00 2001
From: Sebastian Pop <spop at nvidia.com>
Date: Tue, 25 Nov 2025 15:56:39 -0500
Subject: [PATCH] [DA] add testcases for bug #148435
---
.../Analysis/DependenceAnalysis/PR148435.ll | 86 +++++++++++++++++++
.../DependenceAnalysis/bounds-check.ll | 27 ++++++
.../DependenceAnalysis/wrapping-addrec-1.ll | 35 ++++++++
.../DependenceAnalysis/wrapping-addrec.ll | 33 +++++++
4 files changed, 181 insertions(+)
create mode 100644 llvm/test/Analysis/DependenceAnalysis/PR148435.ll
create mode 100644 llvm/test/Analysis/DependenceAnalysis/bounds-check.ll
create mode 100644 llvm/test/Analysis/DependenceAnalysis/wrapping-addrec-1.ll
create mode 100644 llvm/test/Analysis/DependenceAnalysis/wrapping-addrec.ll
diff --git a/llvm/test/Analysis/DependenceAnalysis/PR148435.ll b/llvm/test/Analysis/DependenceAnalysis/PR148435.ll
new file mode 100644
index 0000000000000..54aa9c9399985
--- /dev/null
+++ b/llvm/test/Analysis/DependenceAnalysis/PR148435.ll
@@ -0,0 +1,86 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 | FileCheck %s
+
+define void @_Z1cb(ptr %a) {
+; CHECK-LABEL: '_Z1cb'
+; CHECK-NEXT: Src: store i8 0, ptr %arrayidx9, align 1 --> Dst: store i8 0, ptr %arrayidx9, align 1
+; CHECK-NEXT: da analyze - output [*]!
+;
+entry:
+ br label %for.body
+
+for.cond.cleanup.loopexit: ; preds = %for.body
+ ret void
+
+for.body: ; preds = %for.body, %entry
+ %indvars.iv23 = phi i64 [ 0, %entry ], [ %indvars.iv.next24, %for.body ]
+ %idxprom = and i64 %indvars.iv23, 1
+ %arrayidx9 = getelementptr inbounds [0 x [12 x [12 x i8]]], ptr %a, i64 0, i64 %idxprom, i64 0, i64 %indvars.iv23
+ store i8 0, ptr %arrayidx9, align 1
+ %indvars.iv.next24 = add i64 %indvars.iv23, 1
+ %exitcond.not = icmp eq i64 %indvars.iv.next24, 0
+ br i1 %exitcond.not, label %for.cond.cleanup.loopexit, label %for.body
+}
+
+ at a = external global [0 x [12 x [12 x i8]]], align 1
+
+define void @test_siv_no_addrec(i1 %d, i32 %b) {
+; CHECK-LABEL: 'test_siv_no_addrec'
+; CHECK-NEXT: Src: store i8 0, ptr %arrayidx7, align 1 --> Dst: store i8 0, ptr %arrayidx7, align 1
+; CHECK-NEXT: da analyze - output [* *]!
+;
+entry:
+ %conv.val = select i1 %d, i16 1, i16 0
+ br label %for.cond
+
+for.cond: ; preds = %for.inc8, %entry
+ %e.0 = phi i32 [ %b, %entry ], [ %inc9, %for.inc8 ]
+ %cmp = icmp ult i32 %e.0, 10
+ br i1 %cmp, label %for.cond1, label %for.end10
+
+for.cond1: ; preds = %for.inc, %for.cond
+ %f.0 = phi i16 [ %conv.val, %for.cond ], [ %add, %for.inc ]
+ %cmp2 = icmp slt i16 %f.0, 10
+ br i1 %cmp2, label %for.body4, label %for.inc8
+
+for.body4: ; preds = %for.cond1
+ %sub = add i32 %e.0, -3
+ %idxprom = zext i32 %sub to i64
+ %idxprom5 = sext i16 %f.0 to i64
+ %idxprom6 = zext i32 %e.0 to i64
+ %arrayidx7 = getelementptr inbounds [0 x [12 x [12 x i8]]], ptr @a, i64 0, i64 %idxprom, i64 %idxprom5, i64 %idxprom6
+ store i8 0, ptr %arrayidx7, align 1
+ br label %for.inc
+
+for.inc: ; preds = %for.body4
+ %add = add i16 %f.0, 2
+ br label %for.cond1
+
+for.inc8: ; preds = %for.cond1
+ %inc9 = add i32 %e.0, 1
+ br label %for.cond
+
+for.end10: ; preds = %for.cond
+ ret void
+}
+
+define void @f1(ptr %a) {
+; CHECK-LABEL: 'f1'
+; CHECK-NEXT: Src: store i8 0, ptr %idx, align 1 --> Dst: store i8 0, ptr %idx, align 1
+; CHECK-NEXT: da analyze - output [*]!
+;
+entry:
+ br label %loop
+
+loop:
+ %i = phi i64 [ 0, %entry ], [ %i.next, %loop ]
+ %and = and i64 %i, 1
+ %idx = getelementptr inbounds [4 x [4 x i8]], ptr %a, i64 0, i64 %and, i64 %and
+ store i8 0, ptr %idx
+ %i.next = add i64 %i, 1
+ %exitcond.not = icmp slt i64 %i.next, 8
+ br i1 %exitcond.not, label %loop, label %exit
+
+exit:
+ ret void
+}
diff --git a/llvm/test/Analysis/DependenceAnalysis/bounds-check.ll b/llvm/test/Analysis/DependenceAnalysis/bounds-check.ll
new file mode 100644
index 0000000000000..86086f77d2a47
--- /dev/null
+++ b/llvm/test/Analysis/DependenceAnalysis/bounds-check.ll
@@ -0,0 +1,27 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 | FileCheck %s
+
+; Test case for SmallBitVector bounds checking bug in DependenceAnalysis.
+; This test ensures that loop index mapping functions don't cause out-of-bounds
+; access to SmallBitVector when loop depths exceed MaxLevels.
+
+define void @bounds_check_test(ptr %a) {
+; CHECK-LABEL: 'bounds_check_test'
+; CHECK-NEXT: Src: store i8 0, ptr %idx, align 1 --> Dst: store i8 0, ptr %idx, align 1
+; CHECK-NEXT: da analyze - output [*]!
+;
+entry:
+ br label %loop
+
+loop:
+ %i = phi i64 [ 0, %entry ], [ %i.next, %loop ]
+ %and = and i64 %i, 1 ; Creates index 0 or 1
+ %idx = getelementptr inbounds [4 x [4 x i8]], ptr %a, i64 0, i64 %and, i64 %i
+ store i8 0, ptr %idx
+ %i.next = add i64 %i, 1
+ %exitcond.not = icmp slt i64 %i.next, 4
+ br i1 %exitcond.not, label %loop, label %exit
+
+exit:
+ ret void
+}
diff --git a/llvm/test/Analysis/DependenceAnalysis/wrapping-addrec-1.ll b/llvm/test/Analysis/DependenceAnalysis/wrapping-addrec-1.ll
new file mode 100644
index 0000000000000..00ce2e91809c5
--- /dev/null
+++ b/llvm/test/Analysis/DependenceAnalysis/wrapping-addrec-1.ll
@@ -0,0 +1,35 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 | FileCheck %s
+
+; Test case for bug #148435 - SIV test assertion failure
+
+define void @f(ptr %a) {
+; CHECK-LABEL: 'f'
+; CHECK-NEXT: Src: store i8 42, ptr %idx, align 1 --> Dst: store i8 42, ptr %idx, align 1
+; CHECK-NEXT: da analyze - output [* *]!
+;
+entry:
+ br label %loop.i.header
+
+loop.i.header:
+ %i = phi i64 [ 0, %entry ], [ %i.next, %loop.i.latch ]
+ %and.i = and i64 %i, 1
+ br label %loop.j
+
+loop.j:
+ %j = phi i64 [ 0, %loop.i.header ], [ %j.next, %loop.j ]
+ %and.j = and i64 %j, 1
+ %idx = getelementptr [2 x [2 x i8]], ptr %a, i64 0, i64 %and.i, i64 %and.j
+ store i8 42, ptr %idx
+ %j.next = add i64 %j, 1
+ %exitcond.j = icmp eq i64 %j.next, 100
+ br i1 %exitcond.j, label %loop.i.latch, label %loop.j
+
+loop.i.latch:
+ %i.next = add i64 %i, 1
+ %exitcond.i = icmp eq i64 %i.next, 100
+ br i1 %exitcond.i, label %exit, label %loop.i.header
+
+exit:
+ ret void
+}
diff --git a/llvm/test/Analysis/DependenceAnalysis/wrapping-addrec.ll b/llvm/test/Analysis/DependenceAnalysis/wrapping-addrec.ll
new file mode 100644
index 0000000000000..a1693e9d66575
--- /dev/null
+++ b/llvm/test/Analysis/DependenceAnalysis/wrapping-addrec.ll
@@ -0,0 +1,33 @@
+; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5
+; RUN: opt < %s -disable-output "-passes=print<da>" 2>&1 | FileCheck %s
+
+; Test case for wrapping AddRec detection in DependenceAnalysis.
+; This ensures that AddRec expressions that wrap (creating cyclic rather than
+; linear patterns) are rejected from SIV analysis and treated conservatively.
+
+; This test case has a clear dependence pattern that was incorrectly reported as "none!"
+; The issue: {false,+,true} in i1 arithmetic creates pattern (0,1,0,1,0,1,...).
+; - i=0: a[0][0][0], i=1: a[0][1][1], i=2: a[0][0][0], i=3: a[0][1][1], ...
+; - Clear dependencies at distances 2, 4, 6 between iterations accessing same locations.
+; - Strong SIV test was missing these due to treating wrapping pattern as linear.
+
+define void @test_wrapping_i1_addrec(ptr %a) {
+; CHECK-LABEL: 'test_wrapping_i1_addrec'
+; CHECK-NEXT: Src: store i8 0, ptr %idx, align 1 --> Dst: store i8 0, ptr %idx, align 1
+; CHECK-NEXT: da analyze - output [*]!
+;
+entry:
+ br label %loop
+
+loop:
+ %i = phi i64 [ 0, %entry ], [ %i.next, %loop ]
+ %and = and i64 %i, 1
+ %idx = getelementptr inbounds [4 x [4 x i8]], ptr %a, i64 0, i64 %and, i64 %and
+ store i8 0, ptr %idx
+ %i.next = add i64 %i, 1
+ %exitcond.not = icmp slt i64 %i.next, 8
+ br i1 %exitcond.not, label %loop, label %exit
+
+exit:
+ ret void
+}
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