libstdc++/4402

[Paolo Carlini]

After some major reorganizations by Benjamin, little remains useful of
my original patch.
This is a useful starting point versus the current mainline:

    http://gcc.gnu.org/ml/libstdc++/2001-12/msg00008.html

It is important to *accurately* check that all the __builtin_alloca are
correctly dimensioned. Probably the first one could be spared (for the
sake of efficiency) in the common case of _M_convert_float.

Cheers,
P.

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&pr=4402&database=gcc