c++/7432: Changed bitfield allocation strategy in g++ 3.1.1
grigory@stl.sarov.ru
grigory@stl.sarov.ru
Mon Jul 29 06:26:00 GMT 2002
>Number: 7432
>Category: c++
>Synopsis: Changed bitfield allocation strategy in g++ 3.1.1
>Confidential: no
>Severity: serious
>Priority: medium
>Responsible: unassigned
>State: open
>Class: sw-bug
>Submitter-Id: net
>Arrival-Date: Mon Jul 29 05:26:01 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator: Grigory Zagorodnev
>Release: 3.1.1
>Organization:
>Environment:
host: i686-pc-linux-gnu
build: i686-pc-linux-gnu
target: i686-pc-linux-gnu
configured with: ./configure --enable-threads
>Description:
Attached test case expecting the size of complete structure C to be 16 bytes.
struct C {
char c;
int i : 67;
char d;
};
This is what been offered by GNU compiler for a long time. GCC 3.1.1 compiler gives another size of the structure (24 bytes).
I do not see any reason to enlarge space taken by the structure C, moreover I do not see any ABI acknowledgment for this.
So, the bitfield allocation strategy looks to be erroneously changed.
>How-To-Repeat:
$g++ foo.cpp
$a.out
Actuall results (output):
sizeof(C) = 24
offsetof(C, d) = 17
Expected results (output):
sizeof(C) = 16
offsetof(C, d) = 13
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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