Valarray work (Was... Re: Efficiency)

[Gabriel Dos Reis]

Paolo Carlini <pcarlini@suse.de> writes:

| Gabriel Dos Reis wrote:
| 
| >My attention has been called on something more urgent.  Here is the
| >diffs I have for valarray -- no guarantee it compilers and all
| >reasonable instantiations or does something useful.  It contains fixes
| >to issue DJ raised a few week ago and fixes to the non-POD uses with
| >valarray.  I'll flesh it out later.
| >
| >One thing I don't quite remember is what problems we were solving with
| >the explicit instantiations in src/valarray-inst.cc.  Most of the
| >changes here affect inline functions.  You may want to look over ABI
| >breakage issue and see whether they are acceptable to you.
| >  
| >
| Hi Gaby,
| 
| I had a look to the patch and, as far as I can see, doesn't look so
| dangerous from the binary compatibility point of view. Indeed, your are
| removing some functions and adding some but mostly are not exported from
| the library and not part of the external interface. So far so good. The
| only serious problem I can see at the moment is with __valarray_copy
| which, indeed, is instantiated in src/valarray-inst.cc. I noticed that
| immediately because the build fails there:
| 
| ../../../../trunk/libstdc++-v3/src/valarray-inst.cc:43: error:
| '__valarray_copy' is not a template function
| ../../../../trunk/libstdc++-v3/src/valarray-inst.cc: In function 'size_t
| std::__valarray_product(const std::valarray<unsigned int>&)':
| ../../../../trunk/libstdc++-v3/src/valarray-inst.cc:60: error: invalid
| initialization of reference of type 'const std::valarray<unsigned int>&'
| from expression of type 'unsigned int*'
| ../../../../trunk/libstdc++-v3/src/valarray-inst.cc:52: error: in
| passing argument 1 of 'size_t std::__valarray_product(const
| std::valarray<unsigned int>&)'
| make[2]: *** [valarray-inst.lo] Error 1

I forgot to diff from the libstdc++ top srcdir so that the
modification to src/valarray-inst.cc is included.  Shoot.

| If that is really the only issue (I mostly think so) it would be rather
| easy keeping the code around with the customary "XXX ABI deprecated"
| comment. After all we are only talking about a few lines in
| valarrary_array.h, right? Only the version of __valarray_copy taking a
| pointer, a size and a pointer is exported, therefore would be one small
| function + struct _Array_copier.
| 
| If we agree about the above, then, well, I would ask you to finish up
| the thing, add a couple of testcases (one for the "non-POD issue", one
| for DJ?)...
| 
| Again, please let me know if you want me to help for something...

I'll send a more complete buildable version to you somehwere today.

Thanks!

-- Gaby