Re: [Bug middle-end/29695] [4.1/4.2/4.3 Regression] Folding breaks (a & 0x80) ? 0x80 : 0 for unsigned char or unsigned short a

[Chao-ying Fu]

Sure.  Sorry for the huge log.
I will use your method for the merge commit message in the future.
Thanks a lot!

Regards,
Chao-ying

- Original Message - 
From: "Jakub Jelinek" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Cc: 
Sent: Thursday, November 30, 2006 11:24 PM
Subject: Re: [Bug middle-end/29695] [4.1/4.2/4.3 Regression] Folding breaks
(a & 0x80) ? 0x80 : 0 for unsigned char or unsigned short a


> On Fri, Dec 01, 2006 at 12:07:18AM -, chaoyingfu at gcc dot gnu dot
org wrote:
> >
> >
> > --- Comment #6 from chaoyingfu at gcc dot gnu dot org  2006-12-01
00:07 ---
> > Subject: Bug 29695
> >
> > Author: chaoyingfu
> > Date: Fri Dec  1 00:05:26 2006
> > New Revision: 119383
> >
> > URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=119383
> > Log:
> > Merged revisions 118455-118543 via svnmerge from
> > svn+ssh://[EMAIL PROTECTED]/svn/gcc/trunk
>
> Please, when svn merging to private branches never use all the ChangeLog
entries
> in svn commit messages (it is excessively huge anyway and
> Merged revisions 118455-118543 via svnmerge from
> svn+ssh://[EMAIL PROTECTED]/svn/gcc/trunk
> information is all that is needed), or at least remove
> all PR references from it, as it spams all the PR pages.
>
> Jakub
>

MIPS Maintainer

[Chao-ying Fu]

Hello Matthew and all,

  This is Chao-ying Fu from Wave Computing 
(https://wavecomp.ai/mips-technology/).

  From the GCC MAINTAINERS file, we have the following persons (and more) who 
worked on the MIPS port in the past. 
$ cat MAINTAINERS |grep mips
mips port               Matthew Fortune         
Chao-ying Fu                                    
Maciej W. Rozycki                               
David Ung                                       

  We just wonder if you can sponsor me to become a MIPS maintainer, because 
Wave Computing would like to continue supporting MIPS architecture in GCC, 
although there are very few patches for MIPS recently. Any feedback is welcome.

  Thanks a lot for your help!

Regards,
Chao-ying

Re: [EXTERNAL]Re: MIPS Maintainer

[Chao-ying Fu]

Hi Maciej,

>  Great to hear from you again!

  It's great to hear from you, too!

> >   We just wonder if you can sponsor me to become a MIPS maintainer, 
> > because Wave Computing would like to continue supporting MIPS 
> > architecture in GCC, although there are very few patches for MIPS 
> > recently. Any feedback is welcome.

>  Well, it's up to the GCC steering committee really to appoint maintainers 
> , however you can post patches and help 
> with getting reviews through right away.  There hasn't been much traffic 
> with the MIPS port recently, but there has been some and it always helps 
> to have someone provide input.

  I got David Edelsohn's email and replied to him yesterday.
We have some small tweaks in GCC and can send the patches.
There is a big patch for nanoMIPS that stays as-is for long time.
It will take time to get the patch working against the latest code base,
if the community wants to include nanoMIPS in GCC.

  Thanks a lot!

Regards,
Chao-ying

Re: [EXTERNAL]Re: MIPS Maintainer

[Chao-ying Fu]

Hi Maciej,

> > >  Well, it's up to the GCC steering committee really to appoint 
> > > maintainers 
> > > , however you can post patches and 
> > > help 
> > > with getting reviews through right away.  There hasn't been much traffic 
> > > with the MIPS port recently, but there has been some and it always helps 
> > > to have someone provide input.
> > 
> >   I got David Edelsohn's email and replied to him yesterday.
> > We have some small tweaks in GCC and can send the patches.

>  Please note that GCC is in Stage 3 as from Nov 16th, so if these are bug 
> fixes, then they may still qualify for inclusion with the upcoming GCC 11 
> release expected May-ish next year, but you need to hurry and submit them 
> ASAP.  Otherwise you'll have to wait until trunk reopens for general 
> development around the time of the release.

>  See:  for the release pattern and: 
>  for the most 
> recent status (always linked from the:  home page).

> > There is a big patch for nanoMIPS that stays as-is for long time.
> > It will take time to get the patch working against the latest code base,
> > if the community wants to include nanoMIPS in GCC.

 > I am glad this has not been lost, contrary to the fears I have expressed 
> in a discussion on the MIPS/NetBSD mailing list as recently as last week.

  It's great to know.

>  This is however a major new feature, so it will definitely have to wait 
> for Stage 1.  You may post the patch(es) regardless, however they may not 
> attract much attention as people are busy with QA for GCC 11, especially 
> as in the current situation it is likely it will have to be a general 
> maintainer to approve such a change.  Mind that given how it has been 
> defined the nanoMIPS ISA might be considered an entirely new port/platform 
> though it will depend on how the support for it has been wired into GCC (I 
> don't know the details myself, I wasn't following that development).

>  Also you will have to have binutils support approved and committed first, 
> and given their semiannual release schedule you may well start working on 
> a submission right away, so that at least you have a chance to have that 
> included with the Jul 2021 release (surely you won't make it for the Jan 
> 2021 one).

>  David has kindly explained the rest: just post the changes and have them 
> reviewed, and it's up to the community to decide if a new maintainer is 
> required and if so, who will that be.

  Yes, we will submit patches to get reviewed. Let the community decide if a 
new MIPS maintainer is needed.

>  And last but not least, please make sure you are covered by a copyright 
> assignment with FSF under your current employment.

  Yes, I will try to get a copyright assignment with FSF under Wave Computing.
My old ssh key is not working to clone GCC or Binutils git. I will need some 
help, later.

  Thanks a lot!

Regards,
Chao-ying

Re: writing md rules for fixed-point conversion

[Chao-Ying Fu]

Sean D'Epagnier wrote:

I am working toward efficient support of some of the sfixed point
types on avr architecture.

I started out by writing an assembly library to handle all of the
conversions to and from various fixed point, integer, and floating
point types.  In many cases the functions are only 1 or 2
instructions, so I would like to implement them in the machine
descriptor language so there isn't a function call needed, and the
registers can be used more efficiently.

I was able to get addition of fixed point rules working, eg:

(define_insn "addqq3"
 [(set (match_operand:QQ 0 "register_operand" "=r")
   (plus:QQ (match_operand:QQ 1 "register_operand" "%0")
(match_operand:QQ 2 "register_operand" "r")))]
 ""
 "add %0,%2"
 [(set_attr "length" "1")
  (set_attr "cc" "set_czn")])

This rule works correctly and adds numbers.  The problem is I can't
get conversions to work, and I'm wondering if something is missing in
the compiler elsewhere.  Here is what I tried:

(define_insn "fractqiqq"
 [(set (match_operand:QQ 0 "register_operand" "=r")
   (fract_convert:QQ (match_operand:QI 1 "register_operand"
"0")))]
 ""
 "clr %0"
 [(set_attr "length" "1")
  (set_attr "cc" "set_czn")])

However, it always generates "rcall __fractqiqq" so it isn't using my
rule.  I also found that the fixed point conversions specified at
"http://gcc.gnu.org/onlinedocs/gccint/Conversions.html"; are not used
by any backend currently, so I don't have any examples to work with.

Has anyone used any of the following in machine description?
fract_convert
sat_fract
unsigned_fract_convert
unsigned_sat_fract


I would like some examples.

Thanks,
Sean



Here is one example I made up in 2007 for MIPS backend.  The md file 
contains all possible instruction patterns that GCC may utilize.


Regards,
Chao-ying 


fake-mips-fixed.md
Description: Binary data

Re: Fixed-Point Arithmetic Project

[Chao-ying Fu]

Hello,



  The supported fixed data types are "fixed" in the Embedded-C spec.

Depending on targets, the numbers of integer/fractional

data bits cannot be changed after configuration.  Also, there are no

decimal fixed-point types.

Ex:

1. HQ is a signed 16-bit fractional data type, and the MIPS backend

will configure 15-bit fractional bits and no integer bits.

2. SQ is a signed 32-bit fractional data type, and the MIPS backend

will configure 31-bit fractional bits and no integer bits.



  I am not sure if this meets the need for ADA.  Thanks!


Regards,

Chao-ying

- Original Message - 
From: "Duncan Sands" <[EMAIL PROTECTED]>
To: "Robert Dewar" <[EMAIL PROTECTED]>
Cc: ; "Fu, Chao-Ying" <[EMAIL PROTECTED]>; "Thekkath, Radhika"
<[EMAIL PROTECTED]>; "Stephens, Nigel" <[EMAIL PROTECTED]>; "Arnaud Charlet"
<[EMAIL PROTECTED]>
Sent: Wednesday, October 04, 2006 3:19 AM
Subject: Re: Fixed-Point Arithmetic Project


> On Saturday 23 September 2006 17:08, Robert Dewar wrote:
> > Duncan Sands wrote:
> > >> We are working on a project to add fixed-point arithmetic support to
GCC.
> > >> A GCC project description page is available here
> > >> http://gcc.gnu.org/wiki/FixedPointArithmetic
> > >> and we will create a GCC branch in the near future. If you have
> > >> any suggestions or comments, please respond.
> > >
> > > I expect the Ada front-end people will be interested: the Ada language
> > > incorporates binary and decimal fixed point types.  AFAIK, it is all
> > > done using emulation at the moment.
> >
> > I don't know what emulation means here, obviously there is little
> > hardware support. Ada generates perfectly efficient fixed-point code,
> > but the code is generated in the front end. It might be possible
> > to share back end code if the semantics is exactly what Ada needs.
>
> Making sure the semantics matches what Ada needs is a good reason to get
> involved at this early stage.
>
> Ciao,
>
> Duncan.
>

Re: Fixed-Point Arithmetic Project

[Chao-ying Fu]

I think FSF already has my copyright assignment.  Thanks!

Regards,
Chao-ying

- Original Message - 
From: "Bernd Schmidt" <[EMAIL PROTECTED]>
To: "Fu, Chao-Ying" <[EMAIL PROTECTED]>
Cc: ; "Thekkath, Radhika" <[EMAIL PROTECTED]>; "Stephens,
Nigel" <[EMAIL PROTECTED]>
Sent: Wednesday, October 04, 2006 4:21 AM
Subject: Re: Fixed-Point Arithmetic Project


> Fu, Chao-Ying wrote:
>
> > We are working on a project to add fixed-point arithmetic support to
GCC.
> > A GCC project description page is available here
> > http://gcc.gnu.org/wiki/FixedPointArithmetic
> > and we will create a GCC branch in the near future. If you have
> > any suggestions or comments, please respond.
>
> I'm interested in this kind of thing myself.  Do you have copyright
> assignments in place to assign your work to the FSF?
>
>
> Bernd
>