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* [Bug c++/51060] New: Temporary object stack space is not re-used
@ 2011-11-09 14:11 andvgal at gmail dot com
2011-11-09 14:46 ` [Bug c++/51060] " rguenth at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: andvgal at gmail dot com @ 2011-11-09 14:11 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51060
Bug #: 51060
Summary: Temporary object stack space is not re-used
Classification: Unclassified
Product: gcc
Version: 4.6.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: andvgal@gmail.com
Created attachment 25769
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25769
10 tmp objects of 1KB in size produce 10KB frame
I've tried hard finding a related incident, the only one close to it is PR
16269, but its solution doesn't help.
Attached is a sample test, which allocates 10 temporary objects of 1KB size in
own blocks in the same function.
If compiled with "-Wframe-larger-than=2048 -Werror -Os" (-Oany) the following
warning is produced:
warning: the frame size of 10240 bytes is larger than 2048 bytes
[-Wframe-larger-than=]
In our case, function frames are blown away for 100+KB, what makes a code with
similar pattern absolutely unusable in embedded systems.
Reproduced on GCC 4.6.1 x86_64 @ Debian and custom built GCC 4.6.2 for ARM.
The same issue exists in GCC 4.3.x for ARM.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/51060] Temporary object stack space is not re-used
2011-11-09 14:11 [Bug c++/51060] New: Temporary object stack space is not re-used andvgal at gmail dot com
@ 2011-11-09 14:46 ` rguenth at gcc dot gnu.org
2011-11-11 21:57 ` jason at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: rguenth at gcc dot gnu.org @ 2011-11-09 14:46 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51060
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2011-11-09
CC| |jason at redhat dot com,
| |matz at gcc dot gnu.org
Ever Confirmed|0 |1
--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2011-11-09 14:41:24 UTC ---
Confirmed. The new death-point stuff doesn't help as the frontend does
not seem to construct scopes properly for this testcase.
;; Function void Test() (null)
;; enabled by -tree-original
<<cleanup_point <<< Unknown tree: expr_stmt
(void) TARGET_EXPR <D.21343, <<< Unknown tree: aggr_init_expr
4
__comp_ctor
D.21343
0B >>>> >>>>>;
<<cleanup_point <<< Unknown tree: expr_stmt
(void) TARGET_EXPR <D.21344, <<< Unknown tree: aggr_init_expr
4
__comp_ctor
D.21344
0B >>>> >>>>>;
...
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/51060] Temporary object stack space is not re-used
2011-11-09 14:11 [Bug c++/51060] New: Temporary object stack space is not re-used andvgal at gmail dot com
2011-11-09 14:46 ` [Bug c++/51060] " rguenth at gcc dot gnu.org
@ 2011-11-11 21:57 ` jason at gcc dot gnu.org
2011-11-13 1:20 ` jason at gcc dot gnu.org
2011-11-13 2:06 ` jason at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: jason at gcc dot gnu.org @ 2011-11-11 21:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51060
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
CC| |jason at gcc dot gnu.org
AssignedTo|unassigned at gcc dot |jason at gcc dot gnu.org
|gnu.org |
--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-11 21:50:29 UTC ---
We already deal with cleanups for temporary objects, it should be pretty simple
to add the death clobber that way.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/51060] Temporary object stack space is not re-used
2011-11-09 14:11 [Bug c++/51060] New: Temporary object stack space is not re-used andvgal at gmail dot com
2011-11-09 14:46 ` [Bug c++/51060] " rguenth at gcc dot gnu.org
2011-11-11 21:57 ` jason at gcc dot gnu.org
@ 2011-11-13 1:20 ` jason at gcc dot gnu.org
2011-11-13 2:06 ` jason at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: jason at gcc dot gnu.org @ 2011-11-13 1:20 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51060
--- Comment #3 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-13 00:44:43 UTC ---
Author: jason
Date: Sun Nov 13 00:44:39 2011
New Revision: 181332
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=181332
Log:
PR c++/51060
* gimplify.c (gimplify_target_expr): Add a clobber to the cleanup.
(gimplify_modify_expr): Don't try to simplify it.
* cp/cp-gimplify.c (cp_gimplify_expr): Leave clobbers alone.
Added:
trunk/gcc/testsuite/g++.dg/opt/stack2.C
Modified:
trunk/gcc/ChangeLog
trunk/gcc/cp/ChangeLog
trunk/gcc/cp/cp-gimplify.c
trunk/gcc/gimplify.c
trunk/gcc/testsuite/ChangeLog
trunk/libstdc++-v3/ChangeLog
trunk/libstdc++-v3/testsuite/25_algorithms/max/1.cc
trunk/libstdc++-v3/testsuite/25_algorithms/min/1.cc
trunk/libstdc++-v3/testsuite/25_algorithms/minmax/1.cc
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/51060] Temporary object stack space is not re-used
2011-11-09 14:11 [Bug c++/51060] New: Temporary object stack space is not re-used andvgal at gmail dot com
` (2 preceding siblings ...)
2011-11-13 1:20 ` jason at gcc dot gnu.org
@ 2011-11-13 2:06 ` jason at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: jason at gcc dot gnu.org @ 2011-11-13 2:06 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51060
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|--- |4.7.0
--- Comment #4 from Jason Merrill <jason at gcc dot gnu.org> 2011-11-13 00:47:26 UTC ---
Indeed, pretty simple now that we have that infrastructure.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-11-13 0:48 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2011-11-09 14:11 [Bug c++/51060] New: Temporary object stack space is not re-used andvgal at gmail dot com
2011-11-09 14:46 ` [Bug c++/51060] " rguenth at gcc dot gnu.org
2011-11-11 21:57 ` jason at gcc dot gnu.org
2011-11-13 1:20 ` jason at gcc dot gnu.org
2011-11-13 2:06 ` jason at gcc dot gnu.org
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