[PATCH] rs6000: Fix cpu selection w/ isel (PR100108)

Sebastian Huber sebastian.huber@embedded-brains.de
Mon Jan 17 20:06:25 GMT 2022


On 11/01/2022 09:10, Sebastian Huber wrote:
> Hello Segher,
> 
> On 20/04/2021 17:00, Segher Boessenkool wrote:
>> There are various non-IBM CPUs with isel as well, so it is easiest if we
>> just don't consider that flag here (it is not needed).
>>
>> 2021-04-20  Segher Boessenkool<segher@kernel.crashing.org>
>>
>>     PR target/100108
>>     * config/rs6000/rs6000.c (rs6000_machine_from_flags): Do not consider
>>     OPTION_MASK_ISEL.
>> ---
>> Committed to trunk and 11.  Will do 10 in a week or so.
> 
> sorry for the late response, however, I noticed a GCC build issue with 
> this patch:
> 
> /tmp/sh/b-gcc-powerpc-rtems6/./gcc/xgcc 
> -B/tmp/sh/b-gcc-powerpc-rtems6/./gcc/ -nostdinc 
> -B/tmp/sh/b-gcc-powerpc-rtems6/powerpc-rtems6/m8540/nof/newlib/ -isystem 
> /tmp/sh/b-gcc-powerpc-rtems6/powerpc-rtems6/m8540/nof/newlib/targ-include -isystem 
> /home/EB/sebastian_h/src/gcc/newlib/libc/include 
> -B/tmp/sh/i-powerpc-rtems6/powerpc-rtems6/bin/ 
> -B/tmp/sh/i-powerpc-rtems6/powerpc-rtems6/lib/ -isystem 
> /tmp/sh/i-powerpc-rtems6/powerpc-rtems6/include -isystem 
> /tmp/sh/i-powerpc-rtems6/powerpc-rtems6/sys-include  -mcpu=8540 
> -msoft-float -g -O2 -O2 
> -I/home/EB/sebastian_h/src/gcc/libgcc/../newlib/libc/sys/rtems/include 
> -g -O2 -DIN_GCC  -DCROSS_DIRECTORY_STRUCTURE  -W -Wall -Wno-narrowing 
> -Wwrite-strings -Wcast-qual -Wstrict-prototypes -Wmissing-prototypes 
> -Wold-style-definition  -isystem ./include   -g -DIN_LIBGCC2 
> -fbuilding-libgcc -fno-stack-protector -Dinhibit_libc  -I. -I. 
> -I../../../.././gcc -I/home/EB/sebastian_h/src/gcc/libgcc 
> -I/home/EB/sebastian_h/src/gcc/libgcc/. 
> -I/home/EB/sebastian_h/src/gcc/libgcc/../gcc 
> -I/home/EB/sebastian_h/src/gcc/libgcc/../include  -DHAVE_CC_TLS  -o 
> _negvdi2.o -MT _negvdi2.o -MD -MP -MF _negvdi2.dep -DL_negvdi2 -c 
> /home/EB/sebastian_h/src/gcc/libgcc/libgcc2.c -fvisibility=hidden 
> -DHIDE_EXPORTS
> /tmp/ccZJ18fW.s: Assembler messages:
> /tmp/ccZJ18fW.s:24: Error: unrecognized opcode: `isel'
> make: *** [Makefile:501: _negvdi2.o] Error 1
> 
> The assembler is called like this:
> 
> /tmp/sh/b-gcc-powerpc-rtems6/./gcc/as -I 
> /home/EB/sebastian_h/src/gcc/libgcc/../newlib/libc/sys/rtems/include -I 
> . -I . -I ../../../.././gcc -I /home/EB/sebastian_h/src/gcc/libgcc -I 
> /home/EB/sebastian_h/src/gcc/libgcc/. -I 
> /home/EB/sebastian_h/src/gcc/libgcc/../gcc -I 
> /home/EB/sebastian_h/src/gcc/libgcc/../include -a32 -me500 -mbig -o 
> _negvdi2.o _negvdi2.s
> 
> Using -me500 seems to be all right, however, the file contains a machine 
> directive:
> 
>      .file    "libgcc2.c"
>      .machine ppc
>      .section    ".text"
> 
> If I remove the ".machine ppc" by hand, the file can be assembled with 
> the above command line.
> 
> The affect of the patch is:
> 
> diff -u _negvdi2.s.before _negvdi2.s.after
> --- _negvdi2.s.before   2022-01-11 09:07:43.313828636 +0100
> +++ _negvdi2.s.after    2022-01-11 08:54:08.424946502 +0100
> @@ -1,5 +1,5 @@
>          .file   "libgcc2.c"
> -       .machine power9
> +       .machine ppc
>          .section        ".text"
>   .Ltext0:
>          .align 2
> 
> 

I can try to fix this, however, for me it is not really clear in which 
direction this should be fixed. I can build the GCC 10.3.0 release (it 
uses .machine power9). The GCC 10 branch is broken (it uses .machine 
ppc). Using the .machine directive and a command line option (-me500) 
seems to be a bit inconsistent. It should be one or the other.

Would a patch which changes .machine ppc to .machine e500 for -mcpu=8540 
be the right way to fix this issue?

-- 
embedded brains GmbH
Herr Sebastian HUBER
Dornierstr. 4
82178 Puchheim
Germany
email: sebastian.huber@embedded-brains.de
phone: +49-89-18 94 741 - 16
fax:   +49-89-18 94 741 - 08

Registergericht: Amtsgericht München
Registernummer: HRB 157899
Vertretungsberechtigte Geschäftsführer: Peter Rasmussen, Thomas Dörfler
Unsere Datenschutzerklärung finden Sie hier:
https://embedded-brains.de/datenschutzerklaerung/


More information about the Gcc-patches mailing list