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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/99696] lto looks past aliases to initializers
Date: Mon, 22 Mar 2021 09:15:36 +0000	[thread overview]
Message-ID: <bug-99696-4-Uw406vtqcV@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-99696-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99696

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
     Ever confirmed|0                           |1
      Known to fail|                            |10.2.1, 11.0, 7.5.0
             Status|UNCONFIRMED                 |NEW
            Version|unknown                     |10.2.1
   Last reconfirmed|                            |2021-03-22
          Component|middle-end                  |ipa
                 CC|                            |hubicka at gcc dot gnu.org,
                   |                            |marxin at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Honza, can you please have a look? 

The cgraph dump shows:

x/5 (x) @0x7ffff637b180
  Type: variable definition analyzed
  Visibility: prevailing_def_ironly
  References:
  Referring: y/6 (alias) init/7 (write)
  Read from file: ./a.ltrans0.o
  Availability: available
  Varpool flags:
y/6 (y) @0x7ffff637b080
  Type: variable definition analyzed alias
  Visibility: prevailing_def_ironly
  References: x/5 (alias)
  Referring: main/0 (read)
  Read from file: ./a.ltrans0.o
  Availability: available
  Varpool flags: read-only const-value-known

so indeed somehow the read-only flag is "miscomputed".

OTOH I remember that we chose to "ignore" mismatches in constness for aliases
and thus simply declare this use unsupported (there have been related
bugreports IIRC around const / non-const mixing in aliases).
Note we do not have ODR warnings for y vs. x though.

      parent reply	other threads:[~2021-03-22  9:15 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-21 15:34 [Bug middle-end/99696] New: " rth at gcc dot gnu.org
2021-03-21 17:23 ` [Bug middle-end/99696] " rth at gcc dot gnu.org
2021-03-22  9:15 ` rguenth at gcc dot gnu.org [this message]

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