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From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: Jan Hubicka <hubicka@ucw.cz>
Cc: Vaseeharan Vinayagamoorthy <Vaseeharan.Vinayagamoorthy@arm.com>,
	"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Subject: Re: Fix handling of stores in modref_summary::useful_p
Date: Tue, 6 Oct 2020 09:52:32 +0100	[thread overview]
Message-ID: <20201006085231.GL29000@arm.com> (raw)
In-Reply-To: <20201005214533.GB53551@kam.mff.cuni.cz>

The 10/05/2020 23:45, Jan Hubicka wrote:
> > The 10/05/2020 17:28, Szabolcs Nagy via Gcc-patches wrote:
> > minimal reproducer:
> > 
> > #include <stdio.h>
> > int main()
> > {
> >         int r,t;
> >         r = sscanf("01", "%2x", &t);
> >         printf("scanf: %d  %02x\n", r, t);
> >         return 0;
> > }
> > 
> > should print
> > 
> > scanf: 1  01
> > 
> > but when glibc is compiled with gcc trunk on aarch64 it prints
> > 
> > scanf: 0  00
> > 
> > i will continute the debugging from here tomorrow.
> 
> There is a report on glibc issue here 
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97264
> it turned out to be a latent glibc bug type punning const char * and
> const unsigned char *.
> 
> I wonder if it is same as problem you are seeing?

thanks, that indeed looks very similar, i'll comment on the glibc bug.

      reply	other threads:[~2020-10-06  8:52 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-27 21:46 Jan Hubicka
2020-10-05 11:52 ` Vaseeharan Vinayagamoorthy
2020-10-05 16:28   ` Szabolcs Nagy
2020-10-05 16:54     ` Szabolcs Nagy
2020-10-05 21:45       ` Jan Hubicka
2020-10-06  8:52         ` Szabolcs Nagy [this message]

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