[llvm] [DebugInfo] Fix #76058: missing debug location in processSDiv function (PR #76118)

[Shan Huang via llvm-commits]

https://github.com/Apochens created https://github.com/llvm/llvm-project/pull/76118

This PR fixes #76058 

>From 0a9b7cb8093afe4025c5cdeb1a18c77e6b2453e3 Mon Sep 17 00:00:00 2001
From: Apochens <52285902006 at stu.ecnu.edu.cn>
Date: Thu, 21 Dec 2023 02:33:11 +0000
Subject: [PATCH] [DebugInfo] Fix missing debug location in processSDiv
 function

---
 .../Scalar/CorrelatedValuePropagation.cpp     |  6 ++-
 .../sdiv_missing_debugloc.ll                  | 50 +++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/Transforms/CorrelatedValuePropagation/sdiv_missing_debugloc.ll

diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
index d2dfc764d042bb..c44d3748a80d8b 100644
--- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
+++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp
@@ -935,11 +935,13 @@ static bool processSDiv(BinaryOperator *SDI, const ConstantRange &LCR,
   UDiv->setDebugLoc(SDI->getDebugLoc());
   UDiv->setIsExact(SDI->isExact());
 
-  Value *Res = UDiv;
+  auto *Res = UDiv;
 
   // If the operands had two different domains, we need to negate the result.
-  if (Ops[0].D != Ops[1].D)
+  if (Ops[0].D != Ops[1].D) {
     Res = BinaryOperator::CreateNeg(Res, Res->getName() + ".neg", SDI);
+    Res->setDebugLoc(SDI->getDebugLoc());
+  }
 
   SDI->replaceAllUsesWith(Res);
   SDI->eraseFromParent();
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/sdiv_missing_debugloc.ll b/llvm/test/Transforms/CorrelatedValuePropagation/sdiv_missing_debugloc.ll
new file mode 100644
index 00000000000000..523f58f9872882
--- /dev/null
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/sdiv_missing_debugloc.ll
@@ -0,0 +1,50 @@
+; RUN: opt -passes=correlated-propagation -S < %s | FileCheck %s
+; CHECK: %{{[a-zA-Z0-9_]*}} = udiv i8 %x.nonneg, %y, !dbg ![[DBGLOC:[0-9]+]]
+; CHECK-NEXT: %{{[a-zA-Z0-9_]*}}.neg = sub i8 0, %rem1, !dbg ![[DBGLOC]]
+
+; ModuleID = 'reduced.ll'
+source_filename = "orig.ll"
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
+target triple = "thumbv7m-arm-none-eabi"
+
+; Function Attrs: inaccessiblememonly nocallback nofree nosync nounwind willreturn
+declare void @llvm.assume(i1 noundef) #0
+
+define void @test8_neg_neg(i8 %x, i8 %y) !dbg !5 {
+  %c0 = icmp sle i8 %x, 0, !dbg !13
+  call void @llvm.dbg.value(metadata i1 %c0, metadata !9, metadata !DIExpression()), !dbg !13
+  call void @llvm.assume(i1 %c0), !dbg !14
+  %c1 = icmp sge i8 %y, 0, !dbg !15
+  call void @llvm.dbg.value(metadata i1 %c1, metadata !11, metadata !DIExpression()), !dbg !15
+  call void @llvm.assume(i1 %c1), !dbg !16
+  %rem = sdiv i8 %x, %y, !dbg !17
+  call void @llvm.dbg.value(metadata i8 %rem, metadata !12, metadata !DIExpression()), !dbg !17
+  ret void, !dbg !18
+}
+
+; Function Attrs: nocallback nofree nosync nounwind readnone speculatable willreturn
+declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+!llvm.module.flags = !{!0}
+!llvm.dbg.cu = !{!1}
+!llvm.debugify = !{!3, !4}
+
+!0 = !{i32 2, !"Debug Info Version", i32 3}
+!1 = distinct !DICompileUnit(language: DW_LANG_C, file: !2, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!2 = !DIFile(filename: "reduced.ll", directory: "/")
+!3 = !{i32 6}
+!4 = !{i32 3}
+!5 = distinct !DISubprogram(name: "test8_neg_neg", linkageName: "test8_neg_neg", scope: null, file: !2, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !1, retainedNodes: !8)
+!6 = !DISubroutineType(types: !7)
+!7 = !{}
+!8 = !{!9, !11, !12}
+!9 = !DILocalVariable(name: "1", scope: !5, file: !2, line: 1, type: !10)
+!10 = !DIBasicType(name: "ty8", size: 8, encoding: DW_ATE_unsigned)
+!11 = !DILocalVariable(name: "2", scope: !5, file: !2, line: 3, type: !10)
+!12 = !DILocalVariable(name: "3", scope: !5, file: !2, line: 5, type: !10)
+!13 = !DILocation(line: 1, column: 1, scope: !5)
+!14 = !DILocation(line: 2, column: 1, scope: !5)
+!15 = !DILocation(line: 3, column: 1, scope: !5)
+!16 = !DILocation(line: 4, column: 1, scope: !5)
+!17 = !DILocation(line: 5, column: 1, scope: !5)
+!18 = !DILocation(line: 6, column: 1, scope: !5)
\ No newline at end of file