[PATCH][GCC 7] Remove broken path in extract_bit_field_1

[Richard Biener]

On Mon, Apr 4, 2016 at 3:33 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> On Mon, Apr 04, 2016 at 03:27:23PM +0200, Richard Biener wrote:
>> It ICEs in
>>
>> /space/rguenther/src/svn/trunk/gcc/testsuite/gcc.target/i386/pr37870.c:19:1:
>> internal compiler error: in subreg_get_info, at rtlanal.c:3695
>> 0xddee5a subreg_get_info(unsigned int, machine_mode, unsigned int,
>> machine_mode, subreg_info*)
>>         /space/rguenther/src/svn/trunk/gcc/rtlanal.c:3695
>> 0xddf12b simplify_subreg_regno(unsigned int, machine_mode, unsigned int,
>> machine_mode)
>>         /space/rguenther/src/svn/trunk/gcc/rtlanal.c:3808
>> 0xd8bc7a simplifiable_subregs(subreg_shape const&)
>>         /space/rguenther/src/svn/trunk/gcc/reginfo.c:1234
>> 0xd8be1d record_subregs_of_mode
>>         /space/rguenther/src/svn/trunk/gcc/reginfo.c:1294
>> 0xd8c246 init_subregs_of_mode()
>>         /space/rguenther/src/svn/trunk/gcc/reginfo.c:1348
>> 0xc1a55c init_costs
>>         /space/rguenther/src/svn/trunk/gcc/ira-costs.c:2187
>>
>> which is
>>
>>   /* This should always pass, otherwise we don't know how to verify
>>      the constraint.  These conditions may be relaxed but
>>      subreg_regno_offset would need to be redesigned.  */
>>   gcc_assert ((GET_MODE_SIZE (xmode) % GET_MODE_SIZE (ymode)) == 0);
>
> So perhaps either validate_subreg should check the same thing, or
> the extraction could check this.
> Anyway, I don't have anything against removing that hunk from
> extract_bit_field_1 for GCC7.

Now committed.

Richard.

>         Jakub