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From: "bugdal at aerifal dot cx" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c/94631] Wrong codegen for arithmetic on bitfields
Date: Fri, 17 Apr 2020 20:54:47 +0000	[thread overview]
Message-ID: <bug-94631-4-qi7OHJP3dT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-94631-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94631

--- Comment #8 from Rich Felker <bugdal at aerifal dot cx> ---
OK, I think it's in 6.3.1.1 Boolean, characters, and integers, ¶2, but somewhat
poorly worded:

"The following may be used in an expression wherever an int or unsigned int may
be used: 

- An object or expression with an integer type (other than int or unsigned int)
whose integer conversion rank is less than or equal to the rank of int and
unsigned int.
- A bit-field of type _Bool, int, signed int, or unsigned int.

If an int can represent all values of the original type (as restricted by the
width, for a bit-field), the value is converted to an int; otherwise, it is
converted to an unsigned int. These are called the integer promotions."

The first sentence with second bullet point suggests it should behave as
unsigned int, but the "as restricted by the width, for a bit-field" in the
paragraph after after the bulleted list seems to confirm your interpretation.

  parent reply	other threads:[~2020-04-17 20:54 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-17  4:53 [Bug c/94631] New: " bugdal at aerifal dot cx
2020-04-17  5:09 ` [Bug c/94631] " pinskia at gcc dot gnu.org
2020-04-17  5:17 ` bugdal at aerifal dot cx
2020-04-17  5:34 ` pinskia at gcc dot gnu.org
2020-04-17  8:09 ` rguenth at gcc dot gnu.org
2020-04-17 15:55 ` bugdal at aerifal dot cx
2020-04-17 20:43 ` joseph at codesourcery dot com
2020-04-17 20:50 ` bugdal at aerifal dot cx
2020-04-17 20:54 ` bugdal at aerifal dot cx [this message]
2022-10-26  0:05 ` pinskia at gcc dot gnu.org

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