From: Gunther Nikl <gnikl@justmail.de>
To: stefan@franke.ms (Stefan Franke), gcc-help@gcc.gnu.org
Subject: Re: C and C++ parser performing optimizations
Date: Mon, 24 Aug 2020 21:06:20 +0200 [thread overview]
Message-ID: <20200824210620.00005690@justmail.de> (raw)
In-Reply-To: <000301d66a2a$ad8dcb50$08a961f0$@franke.ms>
stefan@franke.ms (Stefan Franke) wrote:
> > Von: Alexander Monakov <amonakov@ispras.ru>
> > Betreff: Re: C and C++ parser performing optimizations
> >
> > On Sun, 2 Aug 2020, Stefan Franke wrote:
> >
> > > So the parser performs unwanted and uncontrollable optimizations,
> > > which I consider bogus.
> >
> > On occasion they are also incorrect.
> >
> > My (possibly wrong or incomplete) understanding is that GCC does
> > not have internal separation of mandatory simplifications that need
> > to be done in
> the
> > frontend (like constant folding in the context of integer constant
> > expressions) vs. optional simplifications (optimizing
> > substitutions). So it just does both at the same time.
> >
> > Alexander
>
> Here is an example where gcc creates wrong code:
>
> test.c:
> int foo() {
> const char * const txt = "hello";
> register const char * const p asm("ecx") = txt;
> register int dx asm("edx");
> asm(" call _faa" :"=r" (dx) :"rf" (p));
> }
Let me guess: this is about the m68k-amigaos LP macros? Can you show an
example for that target?
Gunther
next prev parent reply other threads:[~2020-08-24 19:09 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-02 18:15 Stefan Franke
2020-08-02 18:40 ` Alexander Monakov
2020-08-04 6:44 ` AW: " Stefan Franke
2020-08-04 7:13 ` Alexander Monakov
2020-08-04 15:33 ` Segher Boessenkool
2020-08-24 19:06 ` Gunther Nikl [this message]
2020-08-24 19:54 ` Stefan Franke
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