Re: GCC fails with -O2 for own Target

[Ian Lance Taylor <iant at google dot com>]

On Wed, Jul 24, 2013 at 6:38 PM, Jens Mehler <jens.mehler@mni.thm.de> wrote:
>
> I have ported the GCC (v4.5.3) to a new target (32-bit RISC processor).
> So far everything went fine. I wrote my own little C-Lib with basic input
> output and tested it worked.
> Until today I never actually tried optimization passes (maybe that was the
> mistake that lead to this)
> Anyway:
> During porting and building Newlib I ran into an error that I tracked down
> to the following code:
>
> unsigned char hexdig[256];
>
> static void htinit ( unsigned char *h , unsigned char *s , int inc)
> {
>     int i, j;
>     for(i = 0; (j = s[i]) !=0; i++)
>         h[j] = i + inc;
> }
>
> void
> hexdig_init ()
> {
>     htinit(hexdig, (unsigned char *) "0123456789", 0x10);
>     htinit(hexdig, (unsigned char *) "abcdef", 0x10 + 10);
>     htinit(hexdig, (unsigned char *) "ABCDEF", 0x10 + 10);
> }
>
> Compiling this code without optimization works like a charm, however
> compiling it with -O2 leads to the following error:
> test1.c: In function 'hexdig_init':
> test1.c:11:1: internal compiler error: in gen_lowpart_general, at
> rtlhooks.c:59
>
> Tried with:
> eco32-gcc -O2 -S test1.c
>
> My question in short is:
> Could this be a targe- backend-error or just some configuration I have
> missed while building GCC?

It is most likely an error in your backend.  The first step is to
break out the debugger and find out why that function is being called
with something that is not a MEM.  You may want to look at
http://gcc.gnu.org/wiki/DebuggingGCC .

Ian