Add .def file for public target instructions

[Andrew Pinski]

On Thu, Jun 25, 2015 at 3:57 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Thu, Jun 25, 2015 at 1:09 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Tue, Jun 23, 2015 at 11:41 AM, Richard Sandiford
>> <rdsandiford@googlemail.com> wrote:
>>> [A fair bit later than promised, sorry...]
>>>
>>> Mikhail posted a patch to make genflags generate the default HAVE_foo
>>> and gen_foo definitions that have recently been added to defaults.h:
>>>
>>>   https://gcc.gnu.org/ml/gcc-patches/2015-06/msg00723.html
>>>
>>> I agree it'd be a good idea to generate this kind of thing automatically,
>>> but I think we should take the opportunity to move the interface to the
>>> target structure.  I.e.:
>>>
>>>   HAVE_foo -> targetm.have_foo ()
>>>   gen_foo -> targetm.gen_foo ()
>>>
>>> This should move us closer to the pipedream goal of supporting multiple
>>> targets at once.  It should also mean that only the target code depends
>>> on insn-flags.h.
>>>
>>> The patch just moves return and simple_return as an example.  I have more
>>> locally (in order to test other code paths), but they're just an obvious
>>> extension of this one.
>>>
>>> The patch relies on the hashing changes in:
>>>
>>>   https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01066.html
>>>   https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01564.html
>>>
>>> and on this trivial patch:
>>>
>>>   https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01604.html
>>>
>>> It seems a bit heavyweight when you just look at these two instructions,
>>> but I think it'll be a saving in the end.
>>>
>>> Bootstrapped & regression-tested on x86_64-linux-gnu.  Also tested
>>> via config-list.mk.  OK to install?
>>>
>>> Thanks,
>>> Richard
>>>
>>>
>>> gcc/
>>>         * Makefile.in (TARGET_DEF): Add target-insns.def.
>>>         (.PRECIOUS, simple_rtl_generated_h): Add insn-target-def.h.
>>>         (build/gentarget-def.o): New rule.
>>>         (genprogrtl): Add target-def.
>>>         * target-insns.def, gentarget-def.c: New files.
>>>         * target.def: Add targetm.have_* and targetm.gen_* hooks,
>>>         based on the contents of target-insns.def.
>>>         * defaults.h (HAVE_simple_return, gen_simple_return): Delete.
>>>         (HAVE_return, gen_return): Delete.
>>>         * target-def.h: Include insn-target-def.h.
>>>         * cfgrtl.c (force_nonfallthru_and_redirect): Use targetm interface
>>>         instead of direct calls.  Rely on them to do the appropriate assertions.
>>>         * function.c (gen_return_pattern): Likewise.  Return an rtx_insn *.
>>>         (convert_jumps_to_returns): Use targetm interface instead of
>>>         direct calls.
>>>         (thread_prologue_and_epilogue_insns): Likewise.
>>>         * reorg.c (find_end_label, dbr_schedule): Likewise.
>>>         * shrink-wrap.h (SHRINK_WRAPPING_ENABLED): Likewise.
>>>         * shrink-wrap.c (convert_to_simple_return): Likewise.
>>>         (try_shrink_wrapping): Use SHRINK_WRAPPING_ENABLED.
>>>
>>
>> This breaks bootstrap on Linux/ia32:
>>
>> https://gcc.gnu.org/ml/gcc-regression/2015-06/msg00649.html
>>
>> ../../src-trunk/gcc/gentarget-def.c: In function âvoid
>> def_target_insn(const char*, const char*)â:
>> ../../src-trunk/gcc/gentarget-def.c:88:34: error: comparison between
>> signed and unsigned integer expressions [-Werror=sign-compare]
>>   if (strtol (p + 1, &endptr, 10) != opno
>>
>
> There are
>
>   unsigned int opno = 0;
>   for (const char *p = prototype; *p; ++p)
>     if (*p == 'x' && ISDIGIT (p[1]))
>       {
>         /* This should be a parameter name of the form "x<OPNO>".
>            That doesn't contribute to the suffix, so skip ahead and
>            process the following character.  */
>         char *endptr;
>         if (strtol (p + 1, &endptr, 10) != opno
>             || (*endptr != ',' && *endptr != ')'))
>
> strtol returns long int.  Somehow, there is no warning on x86-64.

Because on x86_64 (and all LP64 targets), the comparison gets promoted
to long (which is 64bit) so the conversion from unsigned int to long
does not lose precision.

Thanks,
Andrew

>
> --
> H.J.