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[Bug c++/58963] Does C++ need flag_complex_method = 2?
- From: "pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Thu, 14 Nov 2013 18:21:31 +0000
- Subject: [Bug c++/58963] Does C++ need flag_complex_method = 2?
- Auto-submitted: auto-generated
- References: <bug-58963-4 at http dot gcc dot gnu dot org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58963
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Cong Hou from comment #3)
> Suppose there is a third-party complex library, which is written in the same
> way as <complex>. Then GCC could not recognize that as complex type, and
> will not use builtin calls to calculate multiplication and division.
>
> So why there should be a difference when I use the third-party complex lib
> and the standard library lib. After all, <complex> is all written in source
> code. <complex> is not the same as _Complex in C99.
This is like a third party C99 library which does not use _Complex internally
and expands the multiply themselves. I don't see any different here. And yes
I have seen those libraries before (most of them predate C99 too).