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* [Bug optimization/13643] New: __builtin_constant_p() fails to notice known value of member variable
@ 2004-01-11 9:50 bryner at brianryner dot com
2004-01-11 9:51 ` [Bug optimization/13643] " bryner at brianryner dot com
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: bryner at brianryner dot com @ 2004-01-11 9:50 UTC (permalink / raw)
To: gcc-bugs
The testcase can probably demonstrate this better than I can verbalize it.
Basically, I have an object allocated on the stack that initializes a member
variable to a constant. I then call an inlined function on the object which
wants to use __builtin_constant_p() on the member variable. The constant check
evaluates to false... it seems like the compiler should have sufficient
information to determine the value of the member variable. In particular, note
that for struct B in the test case, the |if| in the inline function is optimized
away at compile time. Therefore it seems like __builtin_constant_p() should
evaluate to true in struct A.
(It should be fairly obvious what I'm trying to do here -- eliminate an
unnecessary call to delete(NULL) when mPtr is known to be null at compile time).
--
Summary: __builtin_constant_p() fails to notice known value of
member variable
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: bryner at brianryner dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC host triplet: i686-pc-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13643
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug optimization/13643] __builtin_constant_p() fails to notice known value of member variable 2004-01-11 9:50 [Bug optimization/13643] New: __builtin_constant_p() fails to notice known value of member variable bryner at brianryner dot com @ 2004-01-11 9:51 ` bryner at brianryner dot com 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: bryner at brianryner dot com @ 2004-01-11 9:51 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From bryner at brianryner dot com 2004-01-11 09:51 ------- Created an attachment (id=5450) --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5450&action=view) testcase Compiled with: c++ -Os -c -o test_const.o test_const.cpp $ c++ -v Reading specs from /usr/gcc34/lib/gcc/i686-pc-linux-gnu/3.4.0/specs Configured with: ../gcc/configure --prefix=/usr/gcc34 --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --enable-languages=c,c++ --host=i686-pc-linux-gnu Thread model: posix gcc version 3.4.0 20040110 (experimental) -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13643 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug optimization/13643] __builtin_constant_p() fails to notice known value of member variable 2004-01-11 9:50 [Bug optimization/13643] New: __builtin_constant_p() fails to notice known value of member variable bryner at brianryner dot com 2004-01-11 9:51 ` [Bug optimization/13643] " bryner at brianryner dot com @ 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org 2004-05-13 20:17 ` [Bug tree-optimization/13643] " pinskia at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu dot org @ 2004-01-11 16:07 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-01-11 16:07 ------- Confirmed on the mainline but ... -- What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement Status|UNCONFIRMED |NEW Ever Confirmed| |1 Keywords| |pessimizes-code Last reconfirmed|0000-00-00 00:00:00 |2004-01-11 16:07:05 date| | Target Milestone|--- |tree-ssa Version|unknown |3.4.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13643 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug optimization/13643] __builtin_constant_p() fails to notice known value of member variable 2004-01-11 9:50 [Bug optimization/13643] New: __builtin_constant_p() fails to notice known value of member variable bryner at brianryner dot com 2004-01-11 9:51 ` [Bug optimization/13643] " bryner at brianryner dot com 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org @ 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org 2004-05-13 20:17 ` [Bug tree-optimization/13643] " pinskia at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu dot org @ 2004-01-11 16:07 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-01-11 16:07 ------- Fixed on the tree-ssa already so suspending it. -- What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |SUSPENDED http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13643 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/13643] __builtin_constant_p() fails to notice known value of member variable 2004-01-11 9:50 [Bug optimization/13643] New: __builtin_constant_p() fails to notice known value of member variable bryner at brianryner dot com ` (2 preceding siblings ...) 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org @ 2004-05-13 20:17 ` pinskia at gcc dot gnu dot org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu dot org @ 2004-05-13 20:17 UTC (permalink / raw) To: gcc-bugs ------- Additional Comments From pinskia at gcc dot gnu dot org 2004-05-13 11:33 ------- Fixed for 3.5.0 by the merge of the tree-ssa. -- What |Removed |Added ---------------------------------------------------------------------------- Status|SUSPENDED |RESOLVED Component|rtl-optimization |tree-optimization Resolution| |FIXED Target Milestone|tree-ssa |3.5.0 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13643 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2004-05-13 11:33 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2004-01-11 9:50 [Bug optimization/13643] New: __builtin_constant_p() fails to notice known value of member variable bryner at brianryner dot com 2004-01-11 9:51 ` [Bug optimization/13643] " bryner at brianryner dot com 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org 2004-01-11 16:07 ` pinskia at gcc dot gnu dot org 2004-05-13 20:17 ` [Bug tree-optimization/13643] " pinskia at gcc dot gnu dot org
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