RE: [EXTERNAL] Re: [PATCH][tree-optimization]Optimize combination of comparisons to dec+compare

[Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com>]

Richard,

Can you please commit this patch for me? I don't have write access yet, I'm still working on getting copyright assignment/disclaimer signed by my employer.

Thanks,

Eugene

-----Original Message-----
From: Richard Biener <richard.guenther@gmail.com> 
Sent: Friday, January 15, 2021 3:55 AM
To: Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com>
Cc: gabravier@gmail.com; jakub@gcc.gnu.org; gcc-patches@gcc.gnu.org
Subject: Re: [EXTERNAL] Re: [PATCH][tree-optimization]Optimize combination of comparisons to dec+compare

On Thu, Jan 14, 2021 at 10:04 PM Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com> wrote:
>
> I got more feedback for the patch from Gabriel Ravier and Jakub Jelinek in https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgcc.gnu.org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D96674&amp;data=04%7C01%7CEugene.Rozenfeld%40microsoft.com%7Cf4b1e41de6b4469fd3bb08d8b94c5a20%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637463084866262315%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=%2Fc77uS%2BNlNGmXwOmK729BByEW0VDiq1HEe8BA7DpI30%3D&amp;reserved=0 and re-worked it accordingly.
>
> The changes from the previous patch are:
> 1. Switched the tests to use __attribute__((noipa)) instead of __attribute__((noinline)) .
> 2. Fixed a type in the pattern comment.
> 3. Added :c for top-level bit_ior expression.
> 4. Added :s for the subexpressions.
> 5. Added a pattern for the negated expression:
>     x >= y && y != XXX_MIN --> x > y - 1
>     and the corresponding tests.
>
> The new patch is attached.

OK.

Thanks,
Richard.

> Eugene
>
> -----Original Message-----
> From: Richard Biener <richard.guenther@gmail.com>
> Sent: Tuesday, January 5, 2021 4:21 AM
> To: Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com>
> Cc: gcc-patches@gcc.gnu.org
> Subject: [EXTERNAL] Re: [PATCH][tree-optimization]Optimize combination 
> of comparisons to dec+compare
>
> On Mon, Jan 4, 2021 at 9:50 PM Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com> wrote:
> >
> > Ping.
> >
> > -----Original Message-----
> > From: Eugene Rozenfeld
> > Sent: Tuesday, December 22, 2020 3:01 PM
> > To: Richard Biener <richard.guenther@gmail.com>; 
> > gcc-patches@gcc.gnu.org
> > Subject: RE: Optimize combination of comparisons to dec+compare
> >
> > Re-sending my question and re-attaching the patch.
> >
> > Richard, can you please clarify your feedback?
>
> Hmm, OK.
>
> The patch is OK.
>
> Thanks,
> Richard.
>
>
> > Thanks,
> >
> > Eugene
> >
> > -----Original Message-----
> > From: Gcc-patches <gcc-patches-bounces@gcc.gnu.org> On Behalf Of 
> > Eugene Rozenfeld via Gcc-patches
> > Sent: Tuesday, December 15, 2020 2:06 PM
> > To: Richard Biener <richard.guenther@gmail.com>
> > Cc: gcc-patches@gcc.gnu.org
> > Subject: [EXTERNAL] Re: Optimize combination of comparisons to
> > dec+compare
> >
> > Richard,
> >
> > > Do we already handle x < y || x <= CST to x <= y - CST?
> >
> > That is an invalid transformation: e.g., consider x=3, y=4, CST=2.
> > Can you please clarify?
> >
> > Thanks,
> >
> > Eugene
> >
> > -----Original Message-----
> > From: Richard Biener <richard.guenther@gmail.com>
> > Sent: Thursday, December 10, 2020 12:21 AM
> > To: Eugene Rozenfeld <Eugene.Rozenfeld@microsoft.com>
> > Cc: gcc-patches@gcc.gnu.org
> > Subject: Re: Optimize combination of comparisons to dec+compare
> >
> > On Thu, Dec 10, 2020 at 1:52 AM Eugene Rozenfeld via Gcc-patches <gcc-patches@gcc.gnu.org> wrote:
> > >
> > > This patch adds a pattern for optimizing x < y || x == XXX_MIN to 
> > > x <=
> > > y-1 if y is an integer with TYPE_OVERFLOW_WRAPS.
> >
> > Do we already handle x < y || x <= CST to x <= y - CST?
> > That is, the XXX_MIN case is just a special-case of generic anti-range testing?  For anti-range testing with signed types we pun to unsigned when possible.
> >
> > > This fixes pr96674.
> > >
> > > Tested on x86_64-pc-linux-gnu.
> > >
> > > For this function
> > >
> > > bool f(unsigned a, unsigned b)
> > > {
> > >     return (b == 0) | (a < b);
> > > }
> > >
> > > the code without the patch is
> > >
> > > test   esi,esi
> > > sete   al
> > > cmp    esi,edi
> > > seta   dl
> > > or     eax,edx
> > > ret
> > >
> > > the code with the patch is
> > >
> > > sub    esi,0x1
> > > cmp    esi,edi
> > > setae  al
> > > ret
> > >
> > > Eugene
> > >
> > > gcc/
> > > PR tree-optimization/96674
> > > * match.pd: New pattern x < y || x == XXX_MIN --> x <= y - 1
> > >
> > > gcc/testsuite
> > > * gcc.dg/pr96674.c: New test.
> > >