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. 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
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Rainer Orth, Center for Biotechnology, Bielefeld University
