The following patch solves the 2nd case of
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61578
I did a lot of benchmarking of different heuristics in hard reg cost
propagation in IRA. This is the best what I found. The patch improves
stably code size of SPEC2000 and its score although it is not that
significant.
The patch was tested and bootstrapped on x86-64.
Committed as rev. 228097.
2015-09-24 Vladimir Makarov <vmaka...@redhat.com>
PR target/61578
* ira-color.c (update_allocno_cost): Add parameter.
(update_costs_from_allocno): Decrease conflict cost. Pass the new
parameter.
Index: ira-color.c
===================================================================
--- ira-color.c (revision 227495)
+++ ira-color.c (working copy)
@@ -1311,10 +1311,12 @@ get_next_update_cost (ira_allocno_t *all
return true;
}
-/* Increase costs of HARD_REGNO by UPDATE_COST for ALLOCNO. Return
- true if we really modified the cost. */
+/* Increase costs of HARD_REGNO by UPDATE_COST and conflict cost by
+ UPDATE_CONFLICT_COST for ALLOCNO. Return true if we really
+ modified the cost. */
static bool
-update_allocno_cost (ira_allocno_t allocno, int hard_regno, int update_cost)
+update_allocno_cost (ira_allocno_t allocno, int hard_regno,
+ int update_cost, int update_conflict_cost)
{
int i;
enum reg_class aclass = ALLOCNO_CLASS (allocno);
@@ -1330,7 +1332,7 @@ update_allocno_cost (ira_allocno_t alloc
(&ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (allocno),
aclass, 0, ALLOCNO_CONFLICT_HARD_REG_COSTS (allocno));
ALLOCNO_UPDATED_HARD_REG_COSTS (allocno)[i] += update_cost;
- ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (allocno)[i] += update_cost;
+ ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (allocno)[i] += update_conflict_cost;
return true;
}
@@ -1342,7 +1344,7 @@ static void
update_costs_from_allocno (ira_allocno_t allocno, int hard_regno,
int divisor, bool decr_p, bool record_p)
{
- int cost, update_cost;
+ int cost, update_cost, update_conflict_cost;
machine_mode mode;
enum reg_class rclass, aclass;
ira_allocno_t another_allocno, from = NULL;
@@ -1383,11 +1385,20 @@ update_costs_from_allocno (ira_allocno_t
if (decr_p)
cost = -cost;
- update_cost = cp->freq * cost / divisor;
+ update_conflict_cost = update_cost = cp->freq * cost / divisor;
+
+ if (ALLOCNO_COLOR_DATA (another_allocno) != NULL
+ && (ALLOCNO_COLOR_DATA (allocno)->first_thread_allocno
+ != ALLOCNO_COLOR_DATA (another_allocno)->first_thread_allocno))
+ /* Decrease conflict cost of ANOTHER_ALLOCNO if it is not
+ in the same allocation thread. */
+ update_conflict_cost /= COST_HOP_DIVISOR;
+
if (update_cost == 0)
continue;
- if (! update_allocno_cost (another_allocno, hard_regno, update_cost))
+ if (! update_allocno_cost (another_allocno, hard_regno,
+ update_cost, update_conflict_cost))
continue;
queue_update_cost (another_allocno, allocno, divisor * COST_HOP_DIVISOR);
if (record_p && ALLOCNO_COLOR_DATA (another_allocno) != NULL)
