diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -362,6 +362,8 @@
     DebuggerTuning = DebuggerKind::LLDB;
   else if (TT.isPS4CPU())
     DebuggerTuning = DebuggerKind::SCE;
+  else if (TT.isOSAIX())
+    DebuggerTuning = DebuggerKind::DBX;
   else
     DebuggerTuning = DebuggerKind::GDB;
 
diff --git a/llvm/test/DebugInfo/PowerPC/debugger-tune.ll b/llvm/test/DebugInfo/PowerPC/debugger-tune.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/DebugInfo/PowerPC/debugger-tune.ll
@@ -0,0 +1,41 @@
+; Verify target-based defaults for "debugger tuning," and the ability to
+; override defaults.
+; We use the DW_FORM_string attribute to distinguish the debuggers.
+
+; Verify defaults for various targets.
+; RUN: llc -mtriple=powerpc64le-unknown-linux -filetype=obj < %s | llvm-dwarfdump -debug-info - | FileCheck --check-prefix=GDB %s
+; TODO: Use -filetype-obj and llvm-dwarfdump when the obj mode is supported.
+; RUN: llc -mtriple=powerpc64-ibm-aix-xcoff < %s | FileCheck --check-prefix=DBX %s
+
+; We can override defaults.
+; RUN: llc -mtriple=powerpc64le-unknown-linux -filetype=obj -debugger-tune=dbx < %s | llvm-dwarfdump -debug-info - | FileCheck --check-prefix=DBX %s
+; RUN: llc -mtriple=powerpc64-ibm-aix-xcoff -debugger-tune=gdb < %s | FileCheck --check-prefix=GDB %s
+
+; GDB-NOT: DW_FORM_string
+; DBX-NOT: DW_FORM_strp
+
+; Function Attrs: noinline nounwind optnone
+define i32 @main() #0 !dbg !8 {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval, align 4
+  ret i32 0, !dbg !12
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 12.0.0", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "1.c", directory: "debug")
+!2 = !{}
+!3 = !{i32 7, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 2}
+!6 = !{i32 7, !"PIC Level", i32 2}
+!7 = !{!"clang version 12.0.0"}
+!8 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 1, type: !9, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11}
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!12 = !DILocation(line: 3, column: 3, scope: !8)
diff --git a/llvm/test/DebugInfo/XCOFF/empty.ll b/llvm/test/DebugInfo/XCOFF/empty.ll
--- a/llvm/test/DebugInfo/XCOFF/empty.ll
+++ b/llvm/test/DebugInfo/XCOFF/empty.ll
@@ -1,7 +1,7 @@
 
-; RUN: llc -mtriple powerpc-ibm-aix-xcoff < %s | \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc-ibm-aix-xcoff < %s | \
 ; RUN:   FileCheck %s --check-prefix=ASM32
-; RUN: llc -mtriple powerpc64-ibm-aix-xcoff < %s | \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc64-ibm-aix-xcoff < %s | \
 ; RUN:   FileCheck %s --check-prefix=ASM64
 
 source_filename = "1.c"
diff --git a/llvm/test/DebugInfo/XCOFF/explicit-section.ll b/llvm/test/DebugInfo/XCOFF/explicit-section.ll
--- a/llvm/test/DebugInfo/XCOFF/explicit-section.ll
+++ b/llvm/test/DebugInfo/XCOFF/explicit-section.ll
@@ -1,5 +1,5 @@
 
-; RUN: llc -mtriple powerpc-ibm-aix-xcoff < %s | \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc-ibm-aix-xcoff < %s | \
 ; RUN:   FileCheck %s
 
 source_filename = "2.c"
diff --git a/llvm/test/DebugInfo/XCOFF/function-sections.ll b/llvm/test/DebugInfo/XCOFF/function-sections.ll
--- a/llvm/test/DebugInfo/XCOFF/function-sections.ll
+++ b/llvm/test/DebugInfo/XCOFF/function-sections.ll
@@ -1,5 +1,5 @@
 
-; RUN: llc -mtriple powerpc-ibm-aix-xcoff -function-sections \
+; RUN: llc -debugger-tune=gdb -mtriple powerpc-ibm-aix-xcoff -function-sections \
 ; RUN:   < %s | FileCheck %s
 
 source_filename = "1.c"