[Bug c/81306] valgrind error for function warn_for_multistatement_macros in file c-warn.c line 2474

["mpolacek at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81306

--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
And I wonder if that's what this comment in dump_location_info talks about:

1187       for (unsigned int i = 0; i < MACRO_MAP_NUM_MACRO_TOKENS (map); i++)
1188         {
1189           source_location x = MACRO_MAP_LOCATIONS (map)[2 * i];
1190           source_location y = MACRO_MAP_LOCATIONS (map)[(2 * i) + 1];
1191 
1192           /* linemap_add_macro_token encodes token numbers in an expansion
1193              by putting them after MAP_START_LOCATION. */
1194 
1195           /* I'm typically seeing 4 uninitialized entries at the end of
1196              0xafafafaf.
1197              This appears to be due to macro.c:replace_args
1198              adding 2 extra args for padding tokens; presumably there may
1199              be a leading and/or trailing padding token injected,
1200              each for 2 more location slots.
1201              This would explain there being up to 4 source_locations slots
1202              that may be uninitialized.  */