[llvm] [LiveDebugVariables] Fix a DBG_VALUE reordering issue (PR #111124)

[David Stenberg via llvm-commits]

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@@ -0,0 +1,96 @@
+# RUN: llc -emit-call-site-info %s -mtriple=mips -start-before=register-coalescer -stop-after=virtregrewriter -o - | FileCheck %s
+
+# Verify that LiveDebugVariables does not reorder the stack location DBG_VALUE
+# and the fragmented DBG_VALUEs for aaa, as the latter may represent a stale
+# value. It should also not reorder the DBG_VALUEs for the different variables,
+# as that results in noise in pass before/after diffs.
+
+# CHECK-DAG: ![[aaa:[0-9]+]] = !DILocalVariable(name: "aaa"
+# CHECK-DAG: ![[bbb:[0-9]+]] = !DILocalVariable(name: "bbb"
+# CHECK-DAG: ![[ccc:[0-9]+]] = !DILocalVariable(name: "ccc"
+# CHECK-DAG: ![[ddd:[0-9]+]] = !DILocalVariable(name: "ddd"
+
+# CHECK: DBG_VALUE 1001, $noreg, ![[aaa]], !DIExpression(DW_OP_LLVM_fragment, 0, 16)
+# CHECK-NEXT: DBG_VALUE 1002, $noreg, ![[aaa]], !DIExpression(DW_OP_LLVM_fragment, 16, 16)
+# CHECK-NEXT: DBG_VALUE 222, $noreg, ![[bbb]], !DIExpression()
+# CHECK-NEXT: DBG_VALUE 333, $noreg, ![[ccc]], !DIExpression()
+# CHECK-NEXT: DBG_VALUE 444, $noreg, ![[ddd]], !DIExpression()
+# CHECK-NEXT: DBG_VALUE %stack.0, 0, ![[aaa]], !DIExpression()
+
+--- |
+  target datalayout = "E-m:m-p:32:32-i8:8:32-i16:16:32-i64:64-n32-S64"
+  target triple = "mips"
+
+  ; Function Attrs: nounwind
+  define dso_local i32 @main() local_unnamed_addr #0 !dbg !8 {
+  entry:
+    ret i32 0, !dbg !21
+  }
+
+  declare !dbg !22 dso_local i32 @foo() local_unnamed_addr
+
+  ; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
+  declare void @llvm.dbg.value(metadata, metadata, metadata) #1
+
+  attributes #0 = { nounwind "frame-pointer"="all" }
+  attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
+
+  !llvm.dbg.cu = !{!0}
+  !llvm.module.flags = !{!2, !3, !4, !5, !6}
+  !llvm.ident = !{!7}
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dstenb wrote:

I've removed that, as well as some unneeded line number metadata.

https://github.com/llvm/llvm-project/pull/111124