[Bug c++/67309] New: Error compiling with -std=c++11 and -fsingle-precision-constant

[dflogeras2 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67309

            Bug ID: 67309
           Summary: Error compiling with -std=c++11 and
                    -fsingle-precision-constant
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: dflogeras2 at gmail dot com
  Target Milestone: ---

The ARM people recommend using -fsingle-precision-constant for targeting their
microcontrollers, such as the Cortex M4.  I am experimenting with using parts
of modern C++ on my uC projects.

If I compile the following (not just with arm cross compilers, even my native
linux compiler):

#include <algorithm>
int main() {}

with:
gcc test.cpp -fsingle-precision-constant -std=c++11 -c

It fails, since c++11 templating will not promote float types, and there is an
ambiguous 6.0 floating point constant in the bowels of the STL, which ends up
with a call to std::max<T>( float, double ) which is illegal.

Not sure what the proper fix is, and I'm also not sure why this used to compile
for me (same flags, gcc-4.7.3), but no longer does.