2011-08-22 Dimitrios Apostolou <ji...@gmx.net>
* emit-rtl.c (mem_attrs_htab_hash): Hash massively by calling
iterative_hash(). We disregard the offset,size rtx fields of the
mem_attrs struct, but overall this hash is a *huge* improvement to
the previous one, it reduces the collisions/searches ratio from 8
to 0.8 for some cases.
(init_emit_once): Slightly increase the mem_attrs_htab initial
size because it's frequently used and expanded many times.
=== modified file 'gcc/emit-rtl.c'
--- gcc/emit-rtl.c 2011-05-29 17:40:05 +0000
+++ gcc/emit-rtl.c 2011-08-21 04:44:25 +0000
@@ -256,11 +256,10 @@ mem_attrs_htab_hash (const void *x)
{
const mem_attrs *const p = (const mem_attrs *) x;
- return (p->alias ^ (p->align * 1000)
- ^ (p->addrspace * 4000)
- ^ ((p->offset ? INTVAL (p->offset) : 0) * 50000)
- ^ ((p->size ? INTVAL (p->size) : 0) * 2500000)
- ^ (size_t) iterative_hash_expr (p->expr, 0));
+ /* By massively feeding the mem_attrs struct to iterative_hash() we
+ disregard the p->offset and p->size rtx, but in total the hash is
+ quick and good enough. */
+ return iterative_hash_object (*p, iterative_hash_expr (p->expr, 0));
}
/* Returns nonzero if the value represented by X (which is really a
@@ -5494,7 +5500,7 @@ init_emit_once (void)
const_fixed_htab = htab_create_ggc (37, const_fixed_htab_hash,
const_fixed_htab_eq, NULL);
- mem_attrs_htab = htab_create_ggc (37, mem_attrs_htab_hash,
+ mem_attrs_htab = htab_create_ggc (128, mem_attrs_htab_hash,
mem_attrs_htab_eq, NULL);
reg_attrs_htab = htab_create_ggc (37, reg_attrs_htab_hash,
reg_attrs_htab_eq, NULL);
