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Date: Mon, 16 Jun 2014 09:06:00 -0000
From: Jan Hubicka <hubicka@ucw.cz>
To: Rich Felker <dalias@libc.org>
Cc: Alexander Monakov <amonakov@ispras.ru>, Jeff Law <law@redhat.com>,	Richard Biener <richard.guenther@gmail.com>,	Jan Hubicka <hubicka@ucw.cz>, GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] proposed fix for bug # 61144
Message-ID: <20140616090604.GB14894@kam.mff.cuni.cz>
References: <20140521015948.GA21600@brightrain.aerifal.cx> <CAFiYyc0qj1Yc+VDchBYqsocT4aoyL01CMEB2LmzV3-=TcnHmBg@mail.gmail.com> <20140522035942.GG507@brightrain.aerifal.cx> <537F92CA.8090808@redhat.com> <20140606171424.GC179@brightrain.aerifal.cx> <alpine.LNX.2.00.1406091533270.2730@monopod.intra.ispras.ru> <20140609184601.GI179@brightrain.aerifal.cx>
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> 
> Are the attached files acceptable?

The testcase looks OK to me, but it already should be fixed on mainline
by patch https://gcc.gnu.org/ml/gcc-patches/2014-05/msg01315.html that
prevents dummy to be marked as constant. 

You can however modify the testcase to have
__attribute__ ((weak)) const int foo=0;

This needs your decl_replaceable change to not be optimized to if (0),
because of the explicit const modifier.

I did not change ctor_for_folding to reject variables above as I was not quite
sure we want to support this kind of interposition and I am still not quite certain.
C++ is quite clear about the transformation replacing initialized const by its value.

Honza

> 
> Rich

> /* { dg-do run } */
> /* { dg-require-weak "" } */
> /* { dg-require-alias "" } */
> /* { dg-additional-sources "wkali-3a.c" } */
> 
> #include <stdlib.h>
> 
> static int dummy = 0;
> extern int foo __attribute__((__weak__, __alias__("dummy")));
> 
> int main(void) {
> 
>     if (foo)
>         exit(0);
>     else
>         abort();
> }

> /* { dg-do run } */
> 
> int foo = 1;