Re: [PATCH V2] Use preferred mode for doloop iv [PR61837].

[Iain Sandoe <idsandoe@googlemail.com>]

> On 15 Jul 2021, at 06:09, guojiufu via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> 
> On 2021-07-15 02:04, Segher Boessenkool wrote:
> 

>>> +@deftypefn {Target Hook} machine_mode TARGET_PREFERRED_DOLOOP_MODE
>>> (machine_mode @var{mode})
>>> +This hook takes a @var{mode} which is the original mode of doloop IV.
>>> +And if the target prefers other mode for doloop IV, this hook returns
>>> the
>>> +preferred mode.
>>> +For example, on 64bit target, DImode may be preferred than SImode.
>>> +This hook could return the original mode itself if the target prefer to
>>> +keep the original mode.
>>> +The origianl mode and return mode should be MODE_INT.
>>> +@end deftypefn
>> (Typo, "original").  That has all the right contents, but needs someone
>> who is better at English than me to look at it / improve it.

well.. how about this small tweak?

This hook takes a @var{mode} for a doloop IV, where @code{mode} is the original mode for the operation.  If the target prefers an alternate @code{mode} for the operation, then this hook should return that mode.  For example, on a 64-bit target, @code{DImode} might be preferred over @code{SImode}.  The original @code{mode} should be returned if that is suitable.  Both the original and the returned modes should be @code{MODE_INT}.

0.02GBP only.
Iain