[llvm] [DebugInfo][InferAddressSpaces] Fix the missing debug location update for the new addrspacecast (PR #97038)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,34 @@
+; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -passes=infer-address-spaces -o - %s | FileCheck %s
+
+; Check that InferAddressSpaces's cloneInstructionWithNewAddressSpace() propagates
+; the debug location to new addrspacecast instruction which casts `%p` in the following test.
+
+ at c0 = addrspace(4) global ptr undef
+
+define float @generic_ptr_from_constant() !dbg !5 {
+; CHECK-LABEL: define float @generic_ptr_from_constant(
+; CHECK:    [[TMP1:%.*]] = addrspacecast ptr [[P:%.*]] to ptr addrspace(1), !dbg [[DBG8:![0-9]+]]
+;
+  %p = load ptr, ptr addrspace(4) @c0, align 8, !dbg !8
+  %v = load float, ptr %p, align 4, !dbg !9
+  ret float %v, !dbg !10
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.debugify = !{!2, !3}
+!llvm.module.flags = !{!4}
+
+; CHECK: [[DBG8]] = !DILocation(line: 1,
+;
+!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
+!1 = !DIFile(filename: "temp.ll", directory: "/")
+!2 = !{i32 3}
+!3 = !{i32 0}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = distinct !DISubprogram(name: "generic_ptr_from_constant", linkageName: "generic_ptr_from_constant", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0)
+!6 = !DISubroutineType(types: !7)
+!7 = !{}
+!8 = !DILocation(line: 1, column: 1, scope: !5)
+!9 = !DILocation(line: 2, column: 1, scope: !5)
+!10 = !DILocation(line: 3, column: 1, scope: !5)
+
----------------
arsenm wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/97038