Faster compilation speed: cache behavior

[David S. Miller]

   From: Zack Weinberg <zack@codesourcery.com>
   Date: Tue, 20 Aug 2002 16:32:46 -0700

   RTX                  Number            Bytes    % Total
 ...
   symbol_ref              388            6208      43.425
 ...
   That is an awful lot of data allocation activity, and an awful lot of
   garbage created, for having done nothing at all.

Most of these RTL objects can be eliminated, search the list archives
forthe subject "DECL_RTL vs. explicit make_decl_rtl calls".  Every
function decl. parsed, even in header files, causes a SYMBOL_REF to
be created and hung off the DECL_RTL of the tree node.