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Re: [v3] support for disabling concept checking



Benjamin Kosnik <bkoz@redhat.com> writes:
> The current concept checking code is buggy. This doesn't turn it off,
> but it does allow one to turn it off and have the library still build
> and link properly.

Another thing i've been meaning to mention about concept checks: they
can add significant overhead to the size of the generated debugging
information -- so much so that i disabled concept checks for the builds
i do some time ago.

Here are the results of a test i did a little while ago.  This tabluates the
object file size for a STL-intensive source file with various compiler
options:

   (no debug info) : 1172252
   -g  : 5984348
   -g -D_STL_NO_CONCEPT_CHECKS : 4112244
   -g -gdwarf-2 : 6039964
   -g -gdwarf-2 -D_STL_NO_CONCEPT_CHECKS : 4023208
   -g -gdwarf-2 -feliminate-dwarf2-dups :  7391764
   -g -gdwarf-2 -feliminate-dwarf2-dups -D_STL_NO_CONCEPT_CHECKS : 5271560

As you can see, having the concept checks on increases the final object file
size by about 50%.  I like the idea of concept checks, but not enough
to lose hundreds of megabytes of disk space to them.

sss


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