[llvm] [DebugInfo] Preserve line and column number when merging debug info. (PR #129960)

[Jeremy Morse via llvm-commits]

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@@ -0,0 +1,65 @@
+; RUN: opt %s -passes=simplifycfg -hoist-common-insts -preserve-merged-debug-info -S | FileCheck %s
+; CHECK: tail call i32 @bar{{.*!dbg !}}[[TAG:[0-9]+]]
+; CHECK: ![[TAG]] = !DILocation(line: 9, column: 16, scope: !9) 
+
+; ModuleID = '../llvm/test/DebugInfo/Inputs/debug-info-merge-call.c'
+source_filename = "../llvm/test/DebugInfo/Inputs/debug-info-merge-call.c"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: nounwind uwtable
+define dso_local i32 @test(i32 noundef %n) local_unnamed_addr #0 !dbg !9 {
+entry:
+  %call = tail call i32 @foo(i32 noundef %n) #2, !dbg !12
+  %cmp1 = icmp sgt i32 %n, 100, !dbg !13
+  br i1 %cmp1, label %if.then, label %if.else, !dbg !13
+
+if.then:                                          ; preds = %entry
+  %call2 = tail call i32 @bar(i32 noundef %n) #2, !dbg !14
+  %add = add nsw i32 %call2, %call, !dbg !15
+  br label %if.end, !dbg !16
+
+if.else:                                          ; preds = %entry
+  %call4 = tail call i32 @bar(i32 noundef %n) #2, !dbg !17
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %r.0 = phi i32 [ %add, %if.then ], [ %call4, %if.else ], !dbg !18
+  ret i32 %r.0, !dbg !19
+}
+
+declare !dbg !20 i32 @foo(i32 noundef) local_unnamed_addr #1
+
+declare !dbg !21 i32 @bar(i32 noundef) local_unnamed_addr #1
+
+attributes #0 = { nounwind uwtable "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #1 = { "no-trapping-math"="true" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cmov,+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "tune-cpu"="generic" }
+attributes #2 = { nounwind }
----------------
jmorse wrote:

Nit -- if we can remove or reduce these attributes that'd be appreciated, it's a future maintenance burden when attributes change otherwise.

https://github.com/llvm/llvm-project/pull/129960