Re: [tree-ssa] Small dominator optimizer compile-time improvement

[Daniel Berlin <dberlin at dberlin dot org>]

> I've always meant to go back and re-combine the three hash tables into
> a single table which didn't require us to create silly tree nodes.  
> That's
> precisely what this patch does.  This also takes us a small step 
> closer to
> a world where the hash table doesn't record statements, but instead 
> records
> operators and operands.
GVN-PRE does this, actually.
Look at lookup_or_add, lookup, add, and build_sets_1.
We also pool allocate any binary/unary tree nodes we *do* have to deal 
with, rather than wasting ggc memory.
It works quite well.
I've attached the latest version, which bootstraps and passes regtests 
on x86 and darwin (there's a tree-flow.h to this that caches the value 
handle that i haven't attached, but the code itself should give you an 
idea of what to do).
I'm waiting till after the merge (and after i finish some more 
commenting) before i submit it.

Attachment: tree-ssa-pre.c
Description: Text document