Re: [PATCH] Simplify/improve fold_Nary_to_constant

[Mark Mitchell <mark at codesourcery dot com>]

Roger Sayle wrote:
> Now that Kazu has reorganized fold's internal APIs, its possible to
> trivially implement fold_binary_to_constant using fold_binary and
> fold_unary_to_constant using fold_unary.  Using the obvious two line
> implementations of these functions, avoids creating the tree node
> that was the original motiviation for these routines, but also allows
> us to catch more optimizations and at the same time reduce the code
> duplication.
>
> This patch shrinks fold-const.c by nearly 500 lines (or by over 4%).
>
> Here are some statistics that show that the potential increase in
> memory usage, due to constructing a tree that we then ignore, is
> negligable:

Of course, I've been advocating reducing memory usage -- but I think 
that saving that much code is worth the price, especially given the 
statistics you posted.  If we really do find that we're wasting much 
memory, then there are other things we can do -- including explicitly 
freeing the memory in the case that we return NULL_TREE.  So, I'd say go 
for it.

--
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304