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Date: Thu, 25 Nov 2004 00:32:00 -0000
From: "jakub at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Message-ID: <20041125003250.18666.jakub@gcc.gnu.org>
Reply-To: gcc-bugzilla@gcc.gnu.org
Subject: [Bug c/18666] New: Conversion of floating point into bit-fields
X-Bugzilla-Reason: CC
X-SW-Source: 2004-11/txt/msg02999.txt.bz2
List-Id: <gcc-bugs.sourceware.org>

Is
/* { dg-do run } */
/* { dg-options "-std=c99 -pedantic-errors } */

struct A { unsigned int i : 1; } a;
extern void abort (void);

int
main (void)
{
  a.i = 16.0;
  if (a.i != 0)
    abort ();
  return 0;
}

a valid test or not?  This worked with 3.4.x and earlier, but doesn't any
longer.  The question is mainly if the type of a.i for the 6.3.1.4/1 purposes
is unsigned int (in this case it would be well-defined, 16 is representable
in unsigned int and storing 16 into unsigned int i : 1 bitfield is defined),
or if the type is integer type with precision 1.

-- 
           Summary: Conversion of floating point into bit-fields
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jakub at gcc dot gnu dot org
                CC: aoliva at redhat dot com,gcc-bugs at gcc dot gnu dot
                    org,joseph at codesourcery dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18666