[Bug c++/33068] New: volatile struct bit fields not treated as volatile

[Bug c++/33068] New: volatile struct bit fields not treated as volatile

[Steve at Zook dot com]

When individual bit field members of a struct/class are declared as volatile,
the generated code may not treat them as volatile (code varies with -O and
-m<processor> choices). Non-bit field volatile members and bit field members of
volatile structs are always treated as volatile. The problem can be worked
around by declaring the entire structure volatile.
m68k-elf-g++ and m68k-elf-gcc both generate the bad code when compiling C++,
however, m68k-elf-gcc generates good code when compiling the same test code as
C. I will attach a test.c file which can be compiled as C or C++.


-- 
           Summary: volatile struct bit fields not treated as volatile
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: Steve at Zook dot com
  GCC host triplet: i686-pc-cygwin
GCC target triplet: m68k-elf


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33068

[Bug c++/33068] volatile struct bit fields not treated as volatile

[Steve at Zook dot com]

------- Comment #1 from Steve at Zook dot com  2007-08-14 17:28 -------
Created an attachment (id=14059)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14059&action=view)
Test C or C++ code fragment

For bad code compile: m68k-elf-gcc -c -save-temps -x c++ test.c
or: m68k-elf-g++ -c -save-temps test.c

note code for ProcedureBitStructVolatile() and
ProcedureBitStructVolatileConst()

for good code compile: m68k-elf-gcc -c -save-temps test.c
or: m68k-elf-g++ -c -save-temps -x c test.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33068

[Bug c++/33068] volatile struct bit fields not treated as volatile

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=33068

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |13.1.0

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Looks working GCC 13:
ProcedureBitStructVolatile():
.LFB12:
        .cfi_startproc
        move.w BitStruct,%d0
        rts

[Bug c++/33068] volatile struct bit fields not treated as volatile

[paolo.carlini at oracle dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33068

Paolo Carlini <paolo.carlini at oracle dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|gcc-bugs at gcc dot gnu.org |schwab@linux-m68k.org

--- Comment #2 from Paolo Carlini <paolo.carlini at oracle dot com> 2013-04-09 17:05:55 UTC ---
Maybe Andreas is willing to revisit this issue.