[EXTERNAL] Re: [PATCH][WIP] PR tree-optimization/101808 Boolean comparison simplification

[Navid Rahimi]

> Did you test Ada with this patch as that is where the "odd" boolean
> types show up?
No I haven't tested Ada yet. Since it is work in progress still [WIP]. Quick question, to prevent applying this optimization to those odd Boolean types in Ada, there should be a check to check whether it is canonical boolean type or signed/unsigned, which should prevent messing with odd Boolean types in Ada.

Best wishes,
Navid.

________________________________________
From: Andrew Pinski <pinskia@gmail.com>
Sent: Tuesday, November 23, 2021 11:33
To: Jeff Law
Cc: Navid Rahimi; Navid Rahimi via Gcc-patches
Subject: [EXTERNAL] Re: [PATCH][WIP] PR tree-optimization/101808 Boolean comparison simplification

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On Tue, Nov 23, 2021 at 11:15 AM Jeff Law via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
>
>
> On 11/23/2021 11:34 AM, Navid Rahimi via Gcc-patches wrote:
> > Hi GCC community,
> >
> > I wanted you take a quick look at this patch to solve this bug [1]. This is the code example for the optimization [2] which does include a link to proof of each different optimization.
> >
> > I think it should be possible to use simpler approach than what Andrew has used here [3].
> >
> > P.S. Tested and verified on Linux x86_64.
> >
> > 1) https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgcc.gnu.org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D101808&data=04%7C01%7Cnavidrahimi%40microsoft.com%7C7b45fdd017874f287caf08d9aeb836ad%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637732928490579680%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=UsE0BbrZpRhrPZZreF%2Bj2spaYmJZuVLc053sWTFG6Ow%3D&reserved=0
> > 2) https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fcompiler-explorer.com%2Fz%2FGc448eE3z&data=04%7C01%7Cnavidrahimi%40microsoft.com%7C7b45fdd017874f287caf08d9aeb836ad%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637732928490579680%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=vGlVXyBqBeABvP8hQGb6paYj1t078rSlLdpI0t6qDlc%3D&reserved=0
> > 3) https://nam06.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgcc.gnu.org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D101808%23c1&data=04%7C01%7Cnavidrahimi%40microsoft.com%7C7b45fdd017874f287caf08d9aeb836ad%7C72f988bf86f141af91ab2d7cd011db47%7C1%7C0%7C637732928490579680%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=DNAyrNo9uZ05FyJYOdc%2BD85Dc9A3VgP95htSfaxRS40%3D&reserved=0
> Don't those match.pd patterns make things worse?  We're taking a single
> expression evaluation (the conditional) and turning it into two logicals
> AFAICT.
>
> For the !x expression, obviously if x is a  constant, then we can
> compute that at compile time and we're going from a single conditional
> to a single logical which is probably a win, but that's not the case
> with this patch AFAICT.

One thing is you could use ! to see if bit_not simplifies down to a
constant which is what I did in the bug report.  But it might be more
useful to use the ^ flag (which I added in a different patch) which
says the bit_xor is removed then accept it.

Note (bit_not @0) is wrong, it should be (bit_xor @0 { booleantrue; }
) as there are boolean types which are signed and/or > 1 precision
which is what I had in my patch.
Did you test Ada with this patch as that is where the "odd" boolean
types show up?

Thanks,
Andrew Pinski


>
> jeff