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From: bangerth@dealii.org To: gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, martin@xemacs.org, nobody@gcc.gnu.org Subject: Re: c++/8936: Declaration of never defined member function changes generated code Date: Thu, 19 Dec 2002 17:03:00 -0000 [thread overview] Message-ID: <20021220010349.27582.qmail@sources.redhat.com> (raw) Synopsis: Declaration of never defined member function changes generated code State-Changed-From-To: open->analyzed State-Changed-By: bangerth State-Changed-When: Thu Dec 19 17:03:48 2002 State-Changed-Why: I can confirm this, and it happens with all versions of gcc up to the present mainline after the BIB merge. The effect can be traced back to the case with no optimizations switched on. There, in foo we have at the beginning subl $24, %esp where we have at the beginning of bar: subl $72, %esp Otherwise the code is identical (apart from the obvious changes in addressing local variables relative to ebp). Why so much stack space is allocated remains a mystery to me, but since the difference in stack allocation is the only thing that remains constant the more optimizations we switch on, this would indeed be interesting to investigate. The existence of a copy constructor (that is indeed not used here) changes something in data structures that should not even be used here. I thought a moment about exception handling, but declaring the copy constructor with throw() does not change anything. I don't think I can be of further help, but this would be something well worth fixing! W. http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=8936
next reply other threads:[~2002-12-20 1:03 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top 2002-12-19 17:03 bangerth [this message] -- strict thread matches above, loose matches on Subject: below -- 2002-12-14 2:56 martin
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