[PATCH] Fix missing info for -march and -mtune wrong values on aarch64 (PR driver/83193).

[Martin Liška]

Hi.

This is fix for one of multiple issues seen in the PR. Note that I also have 
some patches
for the others, but it's not stage4 material in my opinion.
This one is quite obvious and should land in GCC 8.

Output before:
$ ./xgcc -B. -march=sparta /tmp/main.c
cc1: error: unknown value ‘sparta’ for -march

And after:
$ ./xgcc -B. -march=sparta /tmp/main.c
cc1: error: unknown value ‘sparta’ for -march
cc1: note: valid arguments are: armv8-a armv8.1-a armv8.2-a armv8.3-a armv8.4-a;

Ready for trunk?

gcc/ChangeLog:

2018-02-20  Martin Liska  <mli...@suse.cz>

        PR driver/83193
        * config/aarch64/aarch64.c (aarch64_print_hint_for_core_or_arch): Print
        possible values if we don't have a hint.
---
 gcc/config/aarch64/aarch64.c | 3 +++
 1 file changed, 3 insertions(+)



diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 228fd1b908d..5fb18c4ca20 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -10633,6 +10633,9 @@ aarch64_print_hint_for_core_or_arch (const char *str, bool arch)
   if (hint)
     inform (input_location, "valid arguments are: %s;"
 			     " did you mean %qs?", s, hint);
+  else
+    inform (input_location, "valid arguments are: %s;", s);
+
   XDELETEVEC (s);
 }