Re: middle-end/7018: bitfield of type long long treated as int in shift

[Andreas Schwab <schwab@suse.de>]

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The following reply was made to PR middle-end/7018; it has been noted by GNATS.

From: Andreas Schwab <schwab@suse.de>
To: "Christian Ehrhardt" <ehrhardt@mathematik.uni-ulm.de>
Cc: gcc-gnats@gcc.gnu.org, jbeulich@novell.com, gcc-bugs@gcc.gnu.org,
	nobody@gcc.gnu.org, gcc-prs@gcc.gnu.org
Subject: Re: middle-end/7018: bitfield of type long long treated as int in
 shift
Date: Thu, 10 Apr 2003 16:44:20 +0200

 "Christian Ehrhardt" <ehrhardt@mathematik.uni-ulm.de> writes:
 
 |> http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7018
 |> 
 |> This PR is about this piece of code and it complains that the bitfield
 |> is promoted to int instead of unsigned long long in the return statement:
 |> 
 |> struct s {                                               
 |> 	unsigned long long uf:1;
 |> };                                                         
 |> 
 |> unsigned long long utest(const struct s*ps) {
 |> 	    return ps->uf << 32;
 |> }
 |> 
 |> IMHO this is behaviour is correct but the standard is somewhat vague
 |> wrt. bit-fields of other types than _Bool, char and int, so I need a
 |> language lawyer to make the final decision.
 |> 
 |> The standard does state quite clearly that an unsigned int bitfield
 |> with a width less than that of int has to be promoted to int and not to
 |> unsigend int, i.e. there is no implicit conversion of the bitfield to
 |> its "container type".
 
 IMHO the integer conversion rank of this bitfield type (which has
 precision 1) is less than the rank of int, thus it is promoted to int.
 
 Andreas.
 
 -- 
 Andreas Schwab, SuSE Labs, schwab@suse.de
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