[PATCH] aix: Default to DWARF 4

[David Edelsohn via Gcc-patches]

    GCC now defaults to DWARF 5.  AIX only supports DWARF 4 (3.5).

    This patch overrides the default DWARF version to 4 unless explicitly
    stated.

    gcc/ChangeLog:

            * config/rs6000/aix71.h (SUBTARGET_OVERRIDE_OPTIONS): Override
            dwarf_version to 4.
            * config/rs6000/aix72.h (SUBTARGET_OVERRIDE_OPTIONS): Same.

diff --git a/gcc/config/rs6000/aix71.h b/gcc/config/rs6000/aix71.h
index cb250e9871c..3612ed2593b 100644
--- a/gcc/config/rs6000/aix71.h
+++ b/gcc/config/rs6000/aix71.h
@@ -62,6 +62,9 @@ do {
        \
       /* aix/ppc doesn't support -mvsx and -maltivec with Go */
\
       rs6000_isa_flags &= ~(OPTION_MASK_VSX | OPTION_MASK_ALTIVEC);    \
     }                                                                  \
+  if (!global_options_set.x_dwarf_version)                             \
+    /* AIX only supports DWARF 4.  */                                  \
+    dwarf_version = 4;                                                 \
 } while (0)

 #define ASM_SPEC32 "-a32"

diff --git a/gcc/config/rs6000/aix72.h b/gcc/config/rs6000/aix72.h
index 8bcaca47a7b..d34909283cc 100644
--- a/gcc/config/rs6000/aix72.h
+++ b/gcc/config/rs6000/aix72.h
@@ -62,6 +62,9 @@ do {
        \
       /* aix/ppc doesn't support -mvsx and -maltivec with Go */
\
       rs6000_isa_flags &= ~(OPTION_MASK_VSX | OPTION_MASK_ALTIVEC);    \
     }                                                                  \
+  if (!global_options_set.x_dwarf_version)                             \
+    /* AIX only supports DWARF 4.  */                                  \
+    dwarf_version = 4;                                                 \
 } while (0)

 #define ASM_SPEC32 "-a32"