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Re: [Patch][PR91504] Inlining misses some logical operation folding

From: Richard Biener <rguenther at suse dot de>
To: Segher Boessenkool <segher at kernel dot crashing dot org>
Cc: kamlesh kumar <kamleshbhalui at gmail dot com>, gcc-patches at gcc dot gnu dot org
Date: Tue, 27 Aug 2019 09:14:15 +0200 (CEST)
Subject: Re: [Patch][PR91504] Inlining misses some logical operation folding
References: <CABKRkgjqsRUyH+c_yWgaQfzo4a-aBxqQdG+Hb07eeJVNgMok-w@mail.gmail.com> <alpine.LSU.2.20.1908261402000.32458@zhemvz.fhfr.qr> <20190826150150.GS31406@gate.crashing.org>

On Mon, 26 Aug 2019, Segher Boessenkool wrote:

> On Mon, Aug 26, 2019 at 02:04:25PM +0200, Richard Biener wrote:
> > On Mon, 26 Aug 2019, kamlesh kumar wrote:
> > > +/* (~a & b) ^ a  -->   (a | b)   */
> > > +(simplify
> > > + (bit_xor:c (bit_and:cs (bit_not @0) @1) @0)
> > > + (bit_ior @0 @1))
> > > +
> > 
> > Are you sure?
> > 
> > (~1804289383 & 846930886) ^ 1804289383 != 1804289383 | 846930886
> 
> Both are hex 7bfb67e7.
> 
> a|b = a|(b&~a) = a^(b&~a)
> 
> >       if ((~a & b) ^ a != a | b)
> 
> != has higher precedence than ^ and | (and &).

Oops.  Need more coffee (and -Wall).

Patch is OK.

Thanks,
Richard.

References:
- [Patch][PR91504] Inlining misses some logical operation folding
  - From: kamlesh kumar
- Re: [Patch][PR91504] Inlining misses some logical operation folding
  - From: Richard Biener
- Re: [Patch][PR91504] Inlining misses some logical operation folding
  - From: Segher Boessenkool

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