[Bug lto/78787] New: O Color, Where Art Thou? (with -flto)

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78787

            Bug ID: 78787
           Summary: O Color, Where Art Thou? (with -flto)
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
          Assignee: unassigned at gcc dot gnu.org
          Reporter: msebor at gcc dot gnu.org
  Target Milestone: ---

Compiling the program below in an xterm window produces two warnings.  The
first one (-Wunused-parameter) is colorized while the second one
(-Wstringop-overflow=) is not.  I don't know if that's a driver problem or an
lto problem but having become accustomed to the colorized diagnostics the LTO
output decidedly looks lacking in ... well, color.  Explicitly specifying
-fdiagnostics-color=always makes both warnings appear in color.

$ cat z.c && /build/gcc-svn/gcc/xgcc -B /build/gcc-svn/gcc -O2 -Wall -Wextra
-flto z.c
char d[1];

int main (int argc, char *argv[])
{
  __builtin_strcpy (d, argc < 3 ? "123" : "456789");
}
z.c: In function ‘main’:
z.c:3:27: warning: unused parameter ‘argv’ [-Wunused-parameter]
 int main (int argc, char *argv[])
                           ^~~~
z.c: In function ‘main’:
z.c:5:3: warning: ‘__builtin_strcpy’ writing 4 bytes into a region of size 1
overflows the destination [-Wstringop-overflow=]
   __builtin_strcpy (d, argc < 3 ? "123" : "456789");
   ^