On Fri, 2017-05-12 20:14:23 +0100, Graham Markall <graham.markall@embecosm.com> wrote:
> Since the combine pass canonicalises shift-add insns using plus and
> ashift (as opposed to plus and mult which it previously used to do), it
> no longer creates *add_n or *sub_n insns, as the patterns match plus and
> mult only. The outcome of this is that some opportunities to generate
> add{1,2,3} and sub{1,2,3} instructions are missed.

[...]
> diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c
> index 91c28e7..42730d5 100644
> --- a/gcc/config/arc/arc.c
> +++ b/gcc/config/arc/arc.c
> @@ -3483,6 +3483,14 @@ arc_print_operand (FILE *file, rtx x, int code)
>  
>        return;
>  
> +    case 'c':
> +      if (GET_CODE (x) == CONST_INT)
> +        fprintf (file, "%d", INTVAL (x) );
> +      else
> +        output_operand_lossage ("invalid operands to %%c code");
> +
> +      return;
> +


Build robot found something (see log at
http://toolchain.lug-owl.de/buildbot/show_build_details.php?id=704773),
seems to be introduced with the above patch fragment:

g++ -fno-PIE -c   -g -O2 -DIN_GCC  -DCROSS_DIRECTORY_STRUCTURE   -fno-exceptions -fno-rtti -fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings -Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic -Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common  -DHAVE_CONFIG_H -I. -I. -I/home/jbglaw/repos-configlist_mk/gcc/gcc -I/home/jbglaw/repos-configlist_mk/gcc/gcc/. -I/home/jbglaw/repos-configlist_mk/gcc/gcc/../include -I/home/jbglaw/repos-configlist_mk/gcc/gcc/../libcpp/include -I/opt/cfarm/mpc/include  -I/home/jbglaw/repos-configlist_mk/gcc/gcc/../libdecnumber -I/home/jbglaw/repos-configlist_mk/gcc/gcc/../libdecnumber/dpd -I../libdecnumber -I/home/jbglaw/repos-configlist_mk/gcc/gcc/../libbacktrace   -o arc.o -MT arc.o -MMD -MP -MF ./.deps/arc.TPo /home/jbglaw/repos-configlist_mk/gcc/gcc/config/arc/arc.c
/home/jbglaw/repos-configlist_mk/gcc/gcc/config/arc/arc.c: In function ‘void arc_print_operand(FILE*, rtx, int)’:
/home/jbglaw/repos-configlist_mk/gcc/gcc/config/arc/arc.c:3503:41: error: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long int’ [-Werror=format=]
         fprintf (file, "%d", INTVAL (x) );
                                         ^
cc1plus: all warnings being treated as errors


MfG, JBG

-- 
      Jan-Benedict Glaw      jbglaw@lug-owl.de              +49-172-7608481
Signature of:             God put me on earth to accomplish a certain number of
the second  :            things. Right now I am so far behind I will never die.