CTF is supported for C only. Currently, a warning is emitted if the -gctf command line option is specified for a non-C frontend. This warning is also used by the GCC testsuite framework - it skips adding -gctf to the list of debug flags for automated testing, if CTF is not supported for the frontend.
The following warning, however, is not useful in case of LTO: "lto1: note: CTF debug info requested, but not supported for ‘GNU GIMPLE’ frontend" This patch disables the generation of the above warning for GNU GIMPLE. Bootstrapped and regression tested on x86_64. gcc/ChangeLog: * toplev.c (process_options): Do not warn for GNU GIMPLE. --- gcc/toplev.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/gcc/toplev.c b/gcc/toplev.c index e1688aa..511a343 100644 --- a/gcc/toplev.c +++ b/gcc/toplev.c @@ -1416,14 +1416,16 @@ process_options (void) debug_info_level = DINFO_LEVEL_NONE; } - /* CTF is supported for only C at this time. - Compiling with -flto results in frontend language of GNU GIMPLE. */ + /* CTF is supported for only C at this time. */ if (!lang_GNU_C () && ctf_debug_info_level > CTFINFO_LEVEL_NONE) { - inform (UNKNOWN_LOCATION, - "CTF debug info requested, but not supported for %qs frontend", - language_string); + /* Compiling with -flto results in frontend language of GNU GIMPLE. It + is not useful to warn in that case. */ + if (!startswith (lang_hooks.name, "GNU GIMPLE")) + inform (UNKNOWN_LOCATION, + "CTF debug info requested, but not supported for %qs frontend", + language_string); ctf_debug_info_level = CTFINFO_LEVEL_NONE; } -- 1.8.3.1