ack/mach/proto/mcg/pass_phigroups.c
David Given d2c14ca44f Precisely one stack hreg gets allocated for each vreg/congruence group for
eviction; this prevents us from having to worry about moving values from stack
slot to stack slot, which is hard.
2018-09-08 18:59:55 +02:00

107 lines
2.2 KiB
C

#include "mcg.h"
static PMAPOF(struct vreg, struct vreg) phimap;
static void make_phimap(void)
{
int i, j;
phimap.count = 0;
for (i=0; i<cfg.preorder.count; i++)
{
struct basicblock* bb = cfg.preorder.item[i];
/* Registers imported through a phi can come from multiple locations. */
for (j=0; j<bb->phis.count; j++)
{
struct vreg* vreg = bb->phis.item[j].left;
struct phi* phi = bb->phis.item[j].right;
struct vreg* prevvreg = phi->ir->result;
pmap_add(&phimap, vreg, prevvreg);
}
}
}
static void recursively_associate_group(struct phicongruence* c, struct vreg* vreg)
{
int i;
vreg->congruence = c;
array_appendu(&c->vregs, vreg);
tracef('V', "V: %%%d is a member of congruence group %d\n",
vreg->id, c->id);
if (vreg->defined)
{
struct constraint* constraint = pmap_findleft(&vreg->defined->constraints, vreg);
if (c->type == 0)
c->type = vreg->type;
if (c->type != vreg->type)
fatal("tried to add register %%%d of type 0x%x to a phi congruence group of type 0x%x",
vreg->id, vreg->type, c->type);
array_appendu(&c->definitions, vreg->defined);
}
for (;;)
{
struct vreg* child = pmap_findleft(&phimap, vreg);
if (!child)
break;
pmap_remove(&phimap, vreg, child);
recursively_associate_group(c, child);
}
for (;;)
{
struct vreg* child = pmap_findright(&phimap, vreg);
if (!child)
break;
pmap_remove(&phimap, child, vreg);
recursively_associate_group(c, child);
}
}
static void update_vreg_types(struct phicongruence* c)
{
int i;
for (i=0; i<c->vregs.count; i++)
{
struct vreg* vreg = c->vregs.item[i];
if (vreg->type == 0)
vreg->type = c->type;
assert(vreg->type == c->type);
assert(vreg->type != 0);
}
}
static void associate_groups(void)
{
static int number = 0;
while (phimap.count > 0)
{
struct phicongruence* c = calloc(1, sizeof(*c));
c->id = number++;
recursively_associate_group(c, phimap.item[0].left);
update_vreg_types(c);
}
}
void pass_find_phi_congruence_groups(void)
{
make_phimap();
associate_groups();
}
/* vim: set sw=4 ts=4 expandtab : */