[Bug driver/63837] [5 Regression] r217391 causes kernel build errors with GCC_COMPARE_DEBUG=1

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63837

--- Comment #7 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
(In reply to Manuel LÃpez-IbÃÃez from comment #6)
> Thanks for the testcase. It seems that the GCC_COMPARE_DEBUG=0 uses a
> temporary file 
> 
>  ./cc1 -quiet -iprefix
> /home/manuel/test1/217394M/build/gcc/../lib/gcc/x86_64-unknown-linux-gnu/5.0.
> 0/ -isystem ./include -isystem ./include-fixed /dev/null -quiet -dumpbase
> null "-mtune=generic" "-march=x86-64" -auxbase null -Wpointer-sign
> "-fcompare-debug=-gtoggle" "-frandom-seed=0x6daada6b94b95048"
> "-fdump-final-insns=/tmp/cc3xSGvK.gkd" -o /tmp/cc3L00jg.s
> 
> but the GCC_COMPARE_DEBUG=1 uses /dev/null:
> 
>  ./cc1 -quiet -iprefix
> /home/manuel/test1/217394M/build/gcc/../lib/gcc/x86_64-unknown-linux-gnu/5.0.
> 0/ -isystem ./include -isystem ./include-fixed /dev/null -quiet -dumpbase
> null.gk "-mtune=generic" "-march=x86-64" -auxbase null -gtoggle
> -Wpointer-sign -w "-fcompare-debug=-gtoggle" -fcompare-debug-second -o
> /dev/null "-frandom-seed=0x6daada6b94b95048"
> "-fdump-final-insns=/tmp/ccMDEp8L.gk.gkd"
> 
> which triggers the heuristic. I can simply ignore /dev/null when checking
> for input==output. I'm testing this patch:
> 
> Index: gcc.c
> ===================================================================
> --- gcc.c       (revision 217457)
> +++ gcc.c       (working copy)
> @@ -4047,11 +4047,12 @@ process_command (unsigned int decoded_op
>        read_cmdline_option (&global_options, &global_options_set,
>                            decoded_options + j, UNKNOWN_LOCATION,
>                            CL_DRIVER, &handlers, global_dc);
>      }
>  
> -  if (output_file && strcmp (output_file, "-"))
> +  if (output_file && strcmp (output_file, "-")
> +      && strcmp (output_file, HOST_BIT_BUCKET))
>      {
>        int i;
>        for (i = 0; i < n_infiles; i++)
>         if ((!infiles[i].language || infiles[i].language[0] != '*')
>             && canonical_filename_eq (infiles[i].name, output_file))
> Index: toplev.c
> ===================================================================
> --- toplev.c    (revision 217457)
> +++ toplev.c    (working copy)
> @@ -940,11 +940,12 @@ init_asm_output (const char *name)
>           strcat (dumpname, ".s");
>           asm_file_name = dumpname;
>         }
>        if (!strcmp (asm_file_name, "-"))
>         asm_out_file = stdout;
> -      else if (!canonical_filename_eq (asm_file_name, name))
> +      else if (!canonical_filename_eq (asm_file_name, name)
> +              || !strcmp (asm_file_name, HOST_BIT_BUCKET))
>         asm_out_file = fopen (asm_file_name, "w");
>        else
>         /* Use fatal_error (UNKOWN_LOCATION) instead of just fatal_error to
>            prevent gcc from printing the first line in the current file. */
>         fatal_error (UNKNOWN_LOCATION,
> 
> If you can test it on your side, it would be helpful.

Your patch fixes the issue. Thank you.