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From: "giovannibajo at libero dot it" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/16405] [3.4/4.0 Regression] Temporary aggregate copy not elided Date: Thu, 07 Oct 2004 11:51:00 -0000 [thread overview] Message-ID: <20041007115127.12100.qmail@sourceware.org> (raw) In-Reply-To: <20040707115615.16405.guillaume.melquiond@ens-lyon.fr> ------- Additional Comments From giovannibajo at libero dot it 2004-10-07 11:51 ------- Confirmed. This won't probably be fixed in the 3.4 branch, but it should in 4.0 at least. Testcase (same of original description): ------------------------------------ struct T { int a[128]; T &operator+=(T const &v); T operator+(T const &v) const { T t = *this; t += v; return t; } }; extern T a, b, c; void f() { a = b + c; } ------------------------------------ The optimized dump (without the copy constructor) from mainline is: ------------------------------------ void f() () { struct T t; struct T * const this; struct T & v; struct T * D.1598; struct T D.1594; struct T t; <bb 0>: t = b; operator+= (&t, &c); D.1594 = t; a = D.1594; return; } ------------------------------------ So there is one additional temporary which is not removed. I cannot see a regression anymore with the copy constructor, so this bug only tracks this now. Guillaume, if you still see a regression with the copy constructor please open a new bug report. It is wrong to track two different testcases (although similar) in the same report. -- What |Removed |Added ---------------------------------------------------------------------------- CC| |giovannibajo at libero dot | |it Status|UNCONFIRMED |NEW Ever Confirmed| |1 Known to fail| |3.4.3 4.0.0 Known to work| |3.3.4 Last reconfirmed|0000-00-00 00:00:00 |2004-10-07 11:51:22 date| | Summary|Non optimized code when |[3.4/4.0 Regression] |using default copy |Temporary aggregate copy not |constructor |elided Target Milestone|--- |3.4.3 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16405
next prev parent reply other threads:[~2004-10-07 11:51 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2004-07-07 11:56 [Bug c++/16405] New: Non optimized code when using default copy constructor guillaume dot melquiond at ens-lyon dot fr 2004-07-07 15:44 ` [Bug c++/16405] " pinskia at gcc dot gnu dot org 2004-07-19 9:19 ` guillaume dot melquiond at ens-lyon dot fr 2004-10-07 11:51 ` giovannibajo at libero dot it [this message] 2004-11-01 0:45 ` [Bug tree-optimization/16405] [3.4/4.0 Regression] Temporary aggregate copy not elided mmitchel at gcc dot gnu dot org 2004-12-23 4:45 ` [Bug c++/16405] " mmitchel at gcc dot gnu dot org 2004-12-23 8:17 ` cvs-commit at gcc dot gnu dot org 2004-12-23 8:18 ` [Bug c++/16405] [3.4 " mmitchel at gcc dot gnu dot org 2004-12-23 16:27 ` cvs-commit at gcc dot gnu dot org 2005-02-13 18:38 ` cvs-commit at gcc dot gnu dot org 2005-05-19 17:40 ` mmitchel at gcc dot gnu dot org
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