[Bug libstdc++/61458] New: std::aligned_storage is bigger than expected

["redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61458

            Bug ID: 61458
           Summary: std::aligned_storage is bigger than expected
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: enhancement
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: redi at gcc dot gnu.org

#include <type_traits>

static_assert(sizeof(std::aligned_storage<4>::type) == 4, "");


so.cc: In function ‘int main()’:
so.cc:5:3: error: static assertion failed: 
   static_assert(sizeof(std::aligned_storage<4>::type) == 4, "");
   ^


I think this is conforming, but it would be more useful if it passed.

We use the maximum alignment supported for any type, where we should use the
maximum alignment supported for types less than 4 bytes
>From gcc-bugs-return-453572-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Jun 09 20:34:30 2014
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From: "mpolacek at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/36446] unexplained warning in struct initialization
Date: Mon, 09 Jun 2014 20:34:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id6446

--- Comment #8 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Author: mpolacek
Date: Mon Jun  9 20:33:51 2014
New Revision: 211388

URL: http://gcc.gnu.org/viewcvs?rev!1388&root=gcc&view=rev
Log:
    PR c/36446
    * c-typeck.c (error_init): Call inform instead of error_at.
    (pedwarn_init): Call inform instead of pedwarn.
    (warning_init): Call inform instead of warning_at.

    * gcc.dg/Wcxx-compat-6.c: Change dg-warning to dg-message.
    * gcc.dg/array-2.c: Likewise.
    * gcc.dg/array-const-2.c: Likewise.
    * gcc.dg/ucnid-8.c: Likewise.
    * gcc.dg/vla-init-1.c: Likewise.
    * gcc.dg/array-const-3.c: Change dg-error to dg-message.
    * gcc.dg/c99-flex-array-7.c: Likewise.
    * gcc.dg/init-bad-1.c: Likewise.
    * gcc.dg/init-bad-3.c: Likewise.
    * gcc.dg/init-bad-2.c: Change dg-error and dg-warning to dg-message.
    * gcc.dg/pedwarn-init.c: Add dg-warning.
    * gcc.dg/pr53119.c: Remove dg-excess-errors.

Modified:
    trunk/gcc/c/ChangeLog
    trunk/gcc/c/c-typeck.c
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/Wcxx-compat-6.c
    trunk/gcc/testsuite/gcc.dg/array-2.c
    trunk/gcc/testsuite/gcc.dg/array-const-2.c
    trunk/gcc/testsuite/gcc.dg/array-const-3.c
    trunk/gcc/testsuite/gcc.dg/c99-flex-array-7.c
    trunk/gcc/testsuite/gcc.dg/init-bad-1.c
    trunk/gcc/testsuite/gcc.dg/init-bad-2.c
    trunk/gcc/testsuite/gcc.dg/init-bad-3.c
    trunk/gcc/testsuite/gcc.dg/pedwarn-init.c
    trunk/gcc/testsuite/gcc.dg/pr53119.c
    trunk/gcc/testsuite/gcc.dg/ucnid-8.c
    trunk/gcc/testsuite/gcc.dg/vla-init-1.c