Re: [PATCH 4/5] remove param$N_is usage

[Jeff Law <law at redhat dot com>]

On 11/12/14 22:55, tsaunders@mozilla.com wrote:
> From: Trevor Saunders <tsaunders@mozilla.com>
>
> Hi,
>
> The only user of this is splay_tree.  We only have a couple splay trees in ggc
> memory, and it wasn't clear to me any of them were tree based instead of hash
> based for performance reasons, so I chose to just convert them to hash_map
> rather than writing a templated splay tree.
>
> bootstrapped + regtested x86_64-unknown-linux-gnu, ok?
>
> trev
>
> gcc/
>
> 	* hash-map.h (hash_map::iterator): New class.
> 	(hash_map::begin): New method.
> 	(hash_map::end): Likewise.
> 	* alias.c, config/alpha/alpha.c, dwarf2asm.c, omp-low.c, tree.h:
> 	replace splay_tree with hash_map.
Splay trees in the alias code are very very old.  They came in with the 
initial "restrict" support from Mark Mitchell many many years ago.   I 
don't recall the reasoning behind using splay trees instead of hash 
tables or some other data structure.

In cases where you're removing the last remnants of a splay tree in a 
file, please make sure to remove the splay-tree include.

OK with the splay-tree include removal, but if we start to get reports 
that these data structures have become a bottleneck, we'll be looking to 
you to address that problem ;-)

jeff