On 5/20/19 10:43 AM, Rainer Orth wrote:
> Hi Martin,
>
>> On 5/14/19 5:07 PM, Martin Sebor wrote:
>>> On 5/14/19 8:55 AM, Martin Liška wrote:
>>>> On 5/13/19 3:07 PM, Jakub Jelinek wrote:
>>>>> On Mon, May 13, 2019 at 12:14:37PM +0200, Martin Liška wrote:
>>>>>> On 5/10/19 11:21 AM, Jakub Jelinek wrote:
>>>>>>> On Fri, May 10, 2019 at 11:04:12AM +0200, Martin Liška wrote:
>>>>>>>> --- a/gcc/config/i386/i386.h
>>>>>>>> +++ b/gcc/config/i386/i386.h
>>>>>>>> @@ -1906,6 +1906,9 @@ typedef struct ix86_args {
>>>>>>>> #define CLEAR_RATIO(speed) ((speed) ? MIN (6,
>>>>>>>> ix86_cost->move_ratio) : 2)
>>>>>>>> +/* C library provides fast implementation of mempcpy function. */
>>>>>>>> +#define TARGET_HAS_FAST_MEMPCPY_ROUTINE 1
>>>>>>>> +
>>>>>>>
>>>>>>> 1) we shouldn't be adding further target macros, but target hooks
>>>>>>
>>>>>> Done.
>>>>>>
>>>>>>> 2) I don't think this is a property of the x86 target, but of x86 glibc,
>>>>>>> so you should set it on x86 glibc only (i.e. i?86/x86_64 linux
>>>>>>> and hurd
>>>>>>> when using glibc, not newlib, nor bionic/android, nor uclibc, nor
>>>>>>> musl)
>>>>>>
>>>>>> I've implemented the in i386.c with DEFAULT_LIBC == LIBC_GLIBC. Hope
>>>>>> it's correct?
>>>>>
>>>>> No, that would be correct only in the rare SINGLE_LIBC configurations.
>>>>> Either you can do
>>>>> #ifdef OPTION_GLIBC
>>>>> return OPTION_GLIBC;
>>>>> #else
>>>>> return false;
>>>>> #endif
>>>>> or define something in config/linux.h (or .[ch]) that you can then use in
>>>>> i386.c.
>>>>>
>>>>> Jakub
>>>>>
>>>>
>>>> Hi.
>>>>
>>>> You always have nice ideas. I'm sending updated patch which addresses
>>>> both Jakub's
>>>> and Wilco's comments.
>>>>
>>>
>>> index 66cee075018..7bff5cbd313 100644
>>> --- a/gcc/target.def
>>> +++ b/gcc/target.def
>>> @@ -5797,6 +5797,12 @@ DEFHOOK
>>> const char *, (void),
>>> hook_constcharptr_void_null)
>>>
>>> +DEFHOOK
>>> +(has_fast_mempcpy_routine,
>>> + "Return true if a target has a fast mempcpy routine.",
>>> + bool, (void),
>>> + hook_bool_void_false)
>>> +
>>>
>>> Not to be too nit-picky about the name but target.def refers to
>>> functions rather than routines. It also defines a hook called
>>> libc_has_function with the obvious semantics so if there's
>>> a chance that it could be useful to query whether another libc
>>> function is "fast" I would suggest to consider defining the hook
>>> correspondingly, i.e.,
>>>
>>> bool libc_has_fast_function (enum function_class)
>>>
>>> and naming the macro similarly.
>>>
>>> Martin
>>
>> Hi Martin.
>>
>> That's a very good suggestion and I'm implementing that!
>>
>> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> as usual, the new effective-target keyworks needs documenting in
> sourcebuild.texi.
Hi.
It's not a target keywords, but it's a new hook. I've briefly read the file
and I can't find any other hooks mentioned in the file.
Martin
> Besides, it doesn't seem to be a very useful property
> of a target, just a collection for all sorts of properties where we are
> too lazy to introduce a new one that really describes what this is
> about...
>
> Rainer
>
