[Bug libstdc++/67256] [C++11] Global scope contaminated with symbols from mathcalls.h

["michal.fita at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67256

--- Comment #3 from Michał Fita <michal.fita at gmail dot com> ---
Contrary to my expectations #include <cmath> doesn't work either. I would
expect these not declared in global if standard says unspecified, as my logic
whisper that would be more C++ way. I understand then I shouldn't expect to get
this fixed as removing these symbols from global scope would break existing
code?

Interesting thing about declaration in mathcalls.h is that they're surrounded
by _Mdouble_BEGIN_NAMESPACE and _Mdouble_END_NAMESPACE macros, which seem empty
when included from cmath (to my surprise that one redefines all functions in
std on top of what is in math.h). Whether these are empty or not the presence
of _GLIBCPP_USE_NAMESPACES decides.

Now I see it has been mindfully done with purpose: 
- https://gcc.gnu.org/bugzilla/show_bug.cgi?id=6257
- http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#456

Another point to the C++ list on the side "hate".
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Subject: [Bug rtl-optimization/67028] combine bug. Different assumptions about subreg in different places.
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idg028

--- Comment #8 from Segher Boessenkool <segher at gcc dot gnu.org> ---
Author: segher
Date: Tue Aug 18 14:27:50 2015
New Revision: 226971

URL: https://gcc.gnu.org/viewcvs?rev"6971&root=gcc&view=rev
Log:
        PR rtl-optimization/67028
        * combine.c (simplify_comparison): Fix comment.  Rearrange code.
        Add test to see if a const_int fits in the new mode.

gcc/testsuite/
        PR rtl-optimization/67028
        * gcc.dg/pr67028.c: New testcase.

Added:
    branches/gcc-4_9-branch/gcc/testsuite/gcc.dg/pr67028.c
Modified:
    branches/gcc-4_9-branch/gcc/ChangeLog
    branches/gcc-4_9-branch/gcc/combine.c
    branches/gcc-4_9-branch/gcc/testsuite/ChangeLog