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From: "npiggin at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106895] powerpc64 unable to specify even/odd register pairs in extended inline asm
Date: Fri, 07 Jul 2023 00:00:38 +0000	[thread overview]
Message-ID: <bug-106895-4-R0Rk0zrZRP@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106895-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106895

--- Comment #11 from Nicholas Piggin <npiggin at gmail dot com> ---
(In reply to Segher Boessenkool from comment #10)
> (In reply to Nicholas Piggin from comment #9)
> > I don't know why constraint is wrong and mode is right
> 
> Simple: you would need O(2**T*N) constraints for our existing N register
> constraints, together with T features like this.  But only O(2**T) modes at
> most.

I guess that would be annoying if you couldn't have modifiers on constraints or
a bad algorithm for working them out. Fair enough.

> 
> > or why TI doesn't work but PTI apparently would,
> 
> Because this is exactly what PTImode is *for*!

Right I accept it is, I meant I just would not have been able to work it out
(assuming if PTI was documented it would be "Partial Tetra Integer" and be no
more useful than the other P?I type documentation.

> 
> > but I'll take anything that works. Could we
> > get PTI implemented? Does it need a new issue opened?
> 
> It was implemented in 2013.  The restriction to only even pairs was a bugfix,
> also from 2013.
> 
> If you have code like
> 
>   typedef __int128 __attribute__((mode(PTI))) even;
> 
> you get an error like
> 
>   error: no data type for mode 'PTI'
> 
> This needs fixing.  You can keep it in this PR?

Sure,  that would be much appreciated.

  parent reply	other threads:[~2023-07-07  0:00 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-09 11:25 [Bug c/106895] New: powerpc64 strange extended inline asm behaviour with register pairs npiggin at gmail dot com
2022-09-09 11:35 ` [Bug c/106895] " rguenth at gcc dot gnu.org
2022-09-09 11:56 ` [Bug target/106895] " bergner at gcc dot gnu.org
2022-09-13 15:34 ` segher at gcc dot gnu.org
2023-06-15 10:26 ` npiggin at gmail dot com
2023-06-15 12:59 ` pinskia at gcc dot gnu.org
2023-07-03  4:30 ` [Bug target/106895] powerpc64 unable to specify even/odd register pairs in extended inline asm segher at gcc dot gnu.org
2023-07-03 15:45 ` bergner at gcc dot gnu.org
2023-07-03 16:55 ` schwab@linux-m68k.org
2023-07-04 16:18 ` segher at gcc dot gnu.org
2023-07-06 11:17 ` npiggin at gmail dot com
2023-07-06 13:46 ` segher at gcc dot gnu.org
2023-07-07  0:00 ` npiggin at gmail dot com [this message]
2023-07-07 19:31 ` segher at gcc dot gnu.org
2023-07-09  5:06 ` npiggin at gmail dot com

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