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* [Bug c++/23702] New: volatile const members of structures not treated as volatile @ 2005-09-02 19:32 Steve at Zook dot com 2005-09-02 19:34 ` [Bug c++/23702] " Steve at Zook dot com ` (2 more replies) 0 siblings, 3 replies; 4+ messages in thread From: Steve at Zook dot com @ 2005-09-02 19:32 UTC (permalink / raw) To: gcc-bugs Volatile const members of a struct are not generating a load when read while volatile non-const members are loaded (volatile const objects outside of a structure do generate a load when read). const members of a volatile struct generate two loads when read (strange code being produced in this case). This has been seen in 3.3.3 (for x86 and m68k targets) and 3.4.4 (for m68k targets, untested on x86). The attached test.cpp file when compiled gcc -c -save-temps test.cpp on 3.3.3 under cygwin (x86 target) produces the attached test.s output. Multiple stores on volatile const members of structs get optimized away as well (this is not demonstrated in the attached test code). Note that when the test code is compiled as C rather than C++, correct code gets produced. -- Summary: volatile const members of structures not treated as volatile Product: gcc Version: 3.4.4 Status: UNCONFIRMED Severity: normal Priority: P2 Component: c++ AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: Steve at Zook dot com CC: gcc-bugs at gcc dot gnu dot org http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23702 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/23702] volatile const members of structures not treated as volatile 2005-09-02 19:32 [Bug c++/23702] New: volatile const members of structures not treated as volatile Steve at Zook dot com @ 2005-09-02 19:34 ` Steve at Zook dot com 2005-09-02 19:36 ` Steve at Zook dot com 2005-09-19 20:07 ` Steve at Zook dot com 2 siblings, 0 replies; 4+ messages in thread From: Steve at Zook dot com @ 2005-09-02 19:34 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From Steve at Zook dot com 2005-09-02 19:33 ------- Created an attachment (id=9652) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9652&action=view) Test code -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23702 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/23702] volatile const members of structures not treated as volatile 2005-09-02 19:32 [Bug c++/23702] New: volatile const members of structures not treated as volatile Steve at Zook dot com 2005-09-02 19:34 ` [Bug c++/23702] " Steve at Zook dot com @ 2005-09-02 19:36 ` Steve at Zook dot com 2005-09-19 20:07 ` Steve at Zook dot com 2 siblings, 0 replies; 4+ messages in thread From: Steve at Zook dot com @ 2005-09-02 19:36 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From Steve at Zook dot com 2005-09-02 19:36 ------- Created an attachment (id=9653) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=9653&action=view) Sample compiled output for test code This sample was compiled: gcc -c -save-temps test.cpp on rev 3.3.3 under Cygwin -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23702 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug c++/23702] volatile const members of structures not treated as volatile 2005-09-02 19:32 [Bug c++/23702] New: volatile const members of structures not treated as volatile Steve at Zook dot com 2005-09-02 19:34 ` [Bug c++/23702] " Steve at Zook dot com 2005-09-02 19:36 ` Steve at Zook dot com @ 2005-09-19 20:07 ` Steve at Zook dot com 2 siblings, 0 replies; 4+ messages in thread From: Steve at Zook dot com @ 2005-09-19 20:07 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From Steve at Zook dot com 2005-09-19 20:06 ------- Test using i686-pc-cygwin with revision 4.0.1 shows problem resolved and good code being emitted (although two new warnings are output about non-local anonymous variables). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23702 ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2005-09-19 20:07 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2005-09-02 19:32 [Bug c++/23702] New: volatile const members of structures not treated as volatile Steve at Zook dot com 2005-09-02 19:34 ` [Bug c++/23702] " Steve at Zook dot com 2005-09-02 19:36 ` Steve at Zook dot com 2005-09-19 20:07 ` Steve at Zook dot com
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