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RFA: patch for accurate updating hard reg costs.
- From: Vladimir Makarov <vmakarov at redhat dot com>
- To: gcc-patches <gcc-patches at gcc dot gnu dot org>
- Cc: Jeff Law <law at redhat dot com>
- Date: Tue, 14 Oct 2008 21:01:46 -0400
- Subject: RFA: patch for accurate updating hard reg costs.
The following patch solves a problem reported for MIPS by Richard
Sandiford in
http://gcc.gnu.org/ml/gcc/2008-09/msg00484.html
Richard reported that it solves some worst problems:
http://gcc.gnu.org/ml/gcc/2008-10/msg00268.html
The patch was successfully tested and bootstrapped on x86_64.
Is it ok to commit the patch to the trunk?
2008-10-14 Vladimir Makarov <vmakarov@redhat.com>
* ira-int.h (ira_allocno): Add member updated_cover_class_cost.
(ALLOCNO_UPDATED_COVER_CLASS_COST): New.
(ira_fast_allocation): Remove the prototype.
* ira-color.c (update_copy_costs, allocno_cost_compare_func,
assign_hard_reg, calculate_allocno_spill_cost): Use updated costs.
(color_pass): Modify the updated costs.
(ira_color): Rename to color. Make it static.
(ira_fast_allocation): Rename to fast_allocation. Make it static.
(ira_color): New function.
* ira-conflicts.c (process_regs_for_copy): Propagate hard reg cost
change.
* ira-lives.c (last_call_num, allocno_saved_at_call): New
variables.
(set_allocno_live, clear_allocno_live, mark_ref_live,
mark_ref_dead): Invalidate corresponding element of
allocno_saved_at_call.
(process_bb_node_lives): Increment last_call_num. Setup
allocno_saved_at_call. Don't increase ALLOCNO_CALL_FREQ if the
allocno was already saved.
(ira_create_allocno_live_ranges): Initiate last_call_num and
allocno_saved_at_call.
* ira-build.c (ira_create_allocno): Initiate
ALLOCNO_UPDATED_COVER_CLASS_COST.
(create_cap_allocno, propagate_allocno_info,
remove_unnecessary_allocnos): Remove setting updated costs.
(ira_flattening): Set up ALLOCNO_UPDATED_COVER_CLASS_COST.
* ira.c (ira): Don't call ira_fast_allocation.
* ira-costs.c (setup_allocno_cover_class_and_costs): Don't set up
updated costs.
Index: ira-conflicts.c
===================================================================
--- ira-conflicts.c (revision 140793)
+++ ira-conflicts.c (working copy)
@@ -337,6 +337,7 @@ process_regs_for_copy (rtx reg1, rtx reg
enum reg_class rclass, cover_class;
enum machine_mode mode;
ira_copy_t cp;
+ ira_loop_tree_node_t parent;
gcc_assert (REG_SUBREG_P (reg1) && REG_SUBREG_P (reg2));
only_regs_p = REG_P (reg1) && REG_P (reg2);
@@ -388,13 +389,23 @@ process_regs_for_copy (rtx reg1, rtx reg
cost = ira_register_move_cost[mode][cover_class][rclass] * freq;
else
cost = ira_register_move_cost[mode][rclass][cover_class] * freq;
- ira_allocate_and_set_costs
- (&ALLOCNO_HARD_REG_COSTS (a), cover_class,
- ALLOCNO_COVER_CLASS_COST (a));
- ira_allocate_and_set_costs
- (&ALLOCNO_CONFLICT_HARD_REG_COSTS (a), cover_class, 0);
- ALLOCNO_HARD_REG_COSTS (a)[index] -= cost;
- ALLOCNO_CONFLICT_HARD_REG_COSTS (a)[index] -= cost;
+ for (;;)
+ {
+ ira_allocate_and_set_costs
+ (&ALLOCNO_HARD_REG_COSTS (a), cover_class,
+ ALLOCNO_COVER_CLASS_COST (a));
+ ira_allocate_and_set_costs
+ (&ALLOCNO_CONFLICT_HARD_REG_COSTS (a), cover_class, 0);
+ ALLOCNO_HARD_REG_COSTS (a)[index] -= cost;
+ ALLOCNO_CONFLICT_HARD_REG_COSTS (a)[index] -= cost;
+ if (ALLOCNO_HARD_REG_COSTS (a)[index] < ALLOCNO_COVER_CLASS_COST (a))
+ ALLOCNO_COVER_CLASS_COST (a) = ALLOCNO_HARD_REG_COSTS (a)[index];
+ if (ALLOCNO_CAP (a) != NULL)
+ a = ALLOCNO_CAP (a);
+ else if ((parent = ALLOCNO_LOOP_TREE_NODE (a)->parent) == NULL
+ || (a = parent->regno_allocno_map[ALLOCNO_REGNO (a)]) == NULL)
+ break;
+ }
return true;
}
Index: ira-int.h
===================================================================
--- ira-int.h (revision 140793)
+++ ira-int.h (working copy)
@@ -258,9 +258,9 @@ struct ira_allocno
/* Register class which should be used for allocation for given
allocno. NO_REGS means that we should use memory. */
enum reg_class cover_class;
- /* Minimal accumulated cost of usage register of the cover class for
- the allocno. */
- int cover_class_cost;
+ /* Minimal accumulated and updated costs of usage register of the
+ cover class for the allocno. */
+ int cover_class_cost, updated_cover_class_cost;
/* Minimal accumulated, and updated costs of memory for the allocno.
At the allocation start, the original and updated costs are
equal. The updated cost may be changed after finishing
@@ -451,6 +451,7 @@ struct ira_allocno
#define ALLOCNO_LEFT_CONFLICTS_NUM(A) ((A)->left_conflicts_num)
#define ALLOCNO_COVER_CLASS(A) ((A)->cover_class)
#define ALLOCNO_COVER_CLASS_COST(A) ((A)->cover_class_cost)
+#define ALLOCNO_UPDATED_COVER_CLASS_COST(A) ((A)->updated_cover_class_cost)
#define ALLOCNO_MEMORY_COST(A) ((A)->memory_cost)
#define ALLOCNO_UPDATED_MEMORY_COST(A) ((A)->updated_memory_cost)
#define ALLOCNO_EXCESS_PRESSURE_POINTS_NUM(A) ((A)->excess_pressure_points_num)
@@ -897,7 +898,6 @@ extern void ira_reassign_conflict_allocn
extern void ira_initiate_assign (void);
extern void ira_finish_assign (void);
extern void ira_color (void);
-extern void ira_fast_allocation (void);
/* ira-emit.c */
extern void ira_emit (bool);
Index: ira-color.c
===================================================================
--- ira-color.c (revision 140793)
+++ ira-color.c (working copy)
@@ -252,7 +252,7 @@ update_copy_costs (ira_allocno_t allocno
ira_allocate_and_set_or_copy_costs
(&ALLOCNO_UPDATED_HARD_REG_COSTS (another_allocno), cover_class,
- ALLOCNO_COVER_CLASS_COST (another_allocno),
+ ALLOCNO_UPDATED_COVER_CLASS_COST (another_allocno),
ALLOCNO_HARD_REG_COSTS (another_allocno));
ira_allocate_and_set_or_copy_costs
(&ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (another_allocno),
@@ -348,8 +348,8 @@ allocno_cost_compare_func (const void *v
ira_allocno_t p2 = *(const ira_allocno_t *) v2p;
int c1, c2;
- c1 = ALLOCNO_UPDATED_MEMORY_COST (p1) - ALLOCNO_COVER_CLASS_COST (p1);
- c2 = ALLOCNO_UPDATED_MEMORY_COST (p2) - ALLOCNO_COVER_CLASS_COST (p2);
+ c1 = ALLOCNO_UPDATED_MEMORY_COST (p1) - ALLOCNO_UPDATED_COVER_CLASS_COST (p1);
+ c2 = ALLOCNO_UPDATED_MEMORY_COST (p2) - ALLOCNO_UPDATED_COVER_CLASS_COST (p2);
if (c1 - c2)
return c1 - c2;
@@ -426,7 +426,9 @@ assign_hard_reg (ira_allocno_t allocno,
#ifdef STACK_REGS
no_stack_reg_p = no_stack_reg_p || ALLOCNO_TOTAL_NO_STACK_REG_P (a);
#endif
- for (cost = ALLOCNO_COVER_CLASS_COST (a), i = 0; i < class_size; i++)
+ for (cost = ALLOCNO_UPDATED_COVER_CLASS_COST (a), i = 0;
+ i < class_size;
+ i++)
if (a_costs != NULL)
{
costs[i] += a_costs[i];
@@ -959,7 +961,7 @@ calculate_allocno_spill_cost (ira_allocn
ira_loop_tree_node_t parent_node, loop_node;
regno = ALLOCNO_REGNO (a);
- cost = ALLOCNO_UPDATED_MEMORY_COST (a) - ALLOCNO_COVER_CLASS_COST (a);
+ cost = ALLOCNO_UPDATED_MEMORY_COST (a) - ALLOCNO_UPDATED_COVER_CLASS_COST (a);
if (ALLOCNO_CAP (a) != NULL)
return cost;
loop_node = ALLOCNO_LOOP_TREE_NODE (a);
@@ -1821,24 +1823,26 @@ color_pass (ira_loop_tree_node_t loop_tr
else
{
cover_class = ALLOCNO_COVER_CLASS (subloop_allocno);
- ira_allocate_and_set_costs
- (&ALLOCNO_HARD_REG_COSTS (subloop_allocno), cover_class,
- ALLOCNO_COVER_CLASS_COST (subloop_allocno));
- ira_allocate_and_set_costs
- (&ALLOCNO_CONFLICT_HARD_REG_COSTS (subloop_allocno),
- cover_class, 0);
cost = (ira_register_move_cost[mode][rclass][rclass]
* (exit_freq + enter_freq));
- ALLOCNO_HARD_REG_COSTS (subloop_allocno)[index] -= cost;
- ALLOCNO_CONFLICT_HARD_REG_COSTS (subloop_allocno)[index]
+ ira_allocate_and_set_or_copy_costs
+ (&ALLOCNO_UPDATED_HARD_REG_COSTS (subloop_allocno), cover_class,
+ ALLOCNO_UPDATED_COVER_CLASS_COST (subloop_allocno),
+ ALLOCNO_HARD_REG_COSTS (subloop_allocno));
+ ira_allocate_and_set_or_copy_costs
+ (&ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (subloop_allocno),
+ cover_class, 0,
+ ALLOCNO_CONFLICT_HARD_REG_COSTS (subloop_allocno));
+ ALLOCNO_UPDATED_HARD_REG_COSTS (subloop_allocno)[index] -= cost;
+ ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (subloop_allocno)[index]
-= cost;
+ if (ALLOCNO_UPDATED_COVER_CLASS_COST (subloop_allocno)
+ > ALLOCNO_UPDATED_HARD_REG_COSTS (subloop_allocno)[index])
+ ALLOCNO_UPDATED_COVER_CLASS_COST (subloop_allocno)
+ = ALLOCNO_UPDATED_HARD_REG_COSTS (subloop_allocno)[index];
ALLOCNO_UPDATED_MEMORY_COST (subloop_allocno)
+= (ira_memory_move_cost[mode][rclass][0] * enter_freq
+ ira_memory_move_cost[mode][rclass][1] * exit_freq);
- if (ALLOCNO_COVER_CLASS_COST (subloop_allocno)
- > ALLOCNO_HARD_REG_COSTS (subloop_allocno)[index])
- ALLOCNO_COVER_CLASS_COST (subloop_allocno)
- = ALLOCNO_HARD_REG_COSTS (subloop_allocno)[index];
}
}
}
@@ -3054,8 +3058,8 @@ ira_finish_assign (void)
/* Entry function doing color-based register allocation. */
-void
-ira_color (void)
+static void
+color (void)
{
allocno_stack_vec = VEC_alloc (ira_allocno_t, heap, ira_allocnos_num);
removed_splay_allocno_vec
@@ -3077,8 +3081,8 @@ ira_color (void)
/* Do register allocation by not using allocno conflicts. It uses
only allocno live ranges. The algorithm is close to Chow's
priority coloring. */
-void
-ira_fast_allocation (void)
+static void
+fast_allocation (void)
{
int i, j, k, num, class_size, hard_regno;
#ifdef STACK_REGS
@@ -3148,3 +3152,24 @@ ira_fast_allocation (void)
if (internal_flag_ira_verbose > 1 && ira_dump_file != NULL)
ira_print_disposition (ira_dump_file);
}
+
+
+
+/* Entry function doing coloring. */
+void
+ira_color (void)
+{
+ ira_allocno_t a;
+ ira_allocno_iterator ai;
+
+ /* Setup updated costs. */
+ FOR_EACH_ALLOCNO (a, ai)
+ {
+ ALLOCNO_UPDATED_MEMORY_COST (a) = ALLOCNO_MEMORY_COST (a);
+ ALLOCNO_UPDATED_COVER_CLASS_COST (a) = ALLOCNO_COVER_CLASS_COST (a);
+ }
+ if (optimize)
+ color ();
+ else
+ fast_allocation ();
+}
Index: ira-lives.c
===================================================================
--- ira-lives.c (revision 140793)
+++ ira-lives.c (working copy)
@@ -75,6 +75,11 @@ static HARD_REG_SET hard_regs_live;
/* The loop tree node corresponding to the current basic block. */
static ira_loop_tree_node_t curr_bb_node;
+/* The number of the last processed call. */
+static int last_call_num;
+/* The number of last call at which given allocno was saved. */
+static int *allocno_saved_at_call;
+
/* The function processing birth of register REGNO. It updates living
hard regs and conflict hard regs for living allocnos or starts a
new live range for the allocno corresponding to REGNO if it is
@@ -163,6 +168,8 @@ set_allocno_live (ira_allocno_t a)
int nregs;
enum reg_class cover_class;
+ /* Invalidate because it is referenced. */
+ allocno_saved_at_call[ALLOCNO_NUM (a)] = 0;
if (sparseset_bit_p (allocnos_live, ALLOCNO_NUM (a)))
return;
sparseset_set_bit (allocnos_live, ALLOCNO_NUM (a));
@@ -189,6 +196,8 @@ clear_allocno_live (ira_allocno_t a)
unsigned int i;
enum reg_class cover_class;
+ /* Invalidate because it is referenced. */
+ allocno_saved_at_call[ALLOCNO_NUM (a)] = 0;
if (sparseset_bit_p (allocnos_live, ALLOCNO_NUM (a)))
{
cover_class = ALLOCNO_COVER_CLASS (a);
@@ -233,7 +242,11 @@ mark_ref_live (struct df_ref *ref)
if (a != NULL)
{
if (sparseset_bit_p (allocnos_live, ALLOCNO_NUM (a)))
- return;
+ {
+ /* Invalidate because it is referenced. */
+ allocno_saved_at_call[ALLOCNO_NUM (a)] = 0;
+ return;
+ }
set_allocno_live (a);
}
make_regno_born (regno);
@@ -305,7 +318,11 @@ mark_ref_dead (struct df_ref *def)
if (a != NULL)
{
if (! sparseset_bit_p (allocnos_live, ALLOCNO_NUM (a)))
- return;
+ {
+ /* Invalidate because it is referenced. */
+ allocno_saved_at_call[ALLOCNO_NUM (a)] = 0;
+ return;
+ }
clear_allocno_live (a);
}
make_regno_dead (regno);
@@ -627,6 +644,9 @@ process_bb_node_lives (ira_loop_tree_nod
if (freq == 0)
freq = 1;
+ /* Invalidate all allocno_saved_at_call entries. */
+ last_call_num++;
+
/* Scan the code of this basic block, noting which allocnos and
hard regs are born or die.
@@ -707,12 +727,21 @@ process_bb_node_lives (ira_loop_tree_nod
if (call_p)
{
+ last_call_num++;
/* The current set of live allocnos are live across the call. */
EXECUTE_IF_SET_IN_SPARSESET (allocnos_live, i)
{
ira_allocno_t a = ira_allocnos[i];
- ALLOCNO_CALL_FREQ (a) += freq;
+ if (allocno_saved_at_call[i] != last_call_num)
+ /* Here we are mimicking caller-save.c behaviour
+ which does not save hard register at a call if
+ it was saved on previous call in the same basic
+ block and the hard register was not mentioned
+ between the two calls. */
+ ALLOCNO_CALL_FREQ (a) += freq;
+ /* Mark it as saved at the next call. */
+ allocno_saved_at_call[i] = last_call_num + 1;
ALLOCNO_CALLS_CROSSED_NUM (a)++;
/* Don't allocate allocnos that cross setjmps or any
call, if this function receives a nonlocal
@@ -946,6 +975,10 @@ ira_create_allocno_live_ranges (void)
{
allocnos_live = sparseset_alloc (ira_allocnos_num);
curr_point = 0;
+ last_call_num = 0;
+ allocno_saved_at_call
+ = (int *) ira_allocate (ira_allocnos_num * sizeof (int));
+ memset (allocno_saved_at_call, 0, ira_allocnos_num * sizeof (int));
ira_traverse_loop_tree (true, ira_loop_tree_root, NULL,
process_bb_node_lives);
ira_max_point = curr_point;
@@ -953,6 +986,7 @@ ira_create_allocno_live_ranges (void)
if (internal_flag_ira_verbose > 2 && ira_dump_file != NULL)
print_live_ranges (ira_dump_file);
/* Clean up. */
+ ira_free (allocno_saved_at_call);
sparseset_free (allocnos_live);
}
Index: ira-build.c
===================================================================
--- ira-build.c (revision 140793)
+++ ira-build.c (working copy)
@@ -469,6 +469,7 @@ ira_create_allocno (int regno, bool cap_
ALLOCNO_UPDATED_CONFLICT_HARD_REG_COSTS (a) = NULL;
ALLOCNO_LEFT_CONFLICTS_NUM (a) = -1;
ALLOCNO_COVER_CLASS (a) = NO_REGS;
+ ALLOCNO_UPDATED_COVER_CLASS_COST (a) = 0;
ALLOCNO_COVER_CLASS_COST (a) = 0;
ALLOCNO_MEMORY_COST (a) = 0;
ALLOCNO_UPDATED_MEMORY_COST (a) = 0;
@@ -769,7 +770,6 @@ create_cap_allocno (ira_allocno_t a)
ALLOCNO_CAP (a) = cap;
ALLOCNO_COVER_CLASS_COST (cap) = ALLOCNO_COVER_CLASS_COST (a);
ALLOCNO_MEMORY_COST (cap) = ALLOCNO_MEMORY_COST (a);
- ALLOCNO_UPDATED_MEMORY_COST (cap) = ALLOCNO_UPDATED_MEMORY_COST (a);
ira_allocate_and_copy_costs
(&ALLOCNO_HARD_REG_COSTS (cap), cover_class, ALLOCNO_HARD_REG_COSTS (a));
ira_allocate_and_copy_costs
@@ -1509,8 +1509,6 @@ propagate_allocno_info (void)
ALLOCNO_COVER_CLASS_COST (parent_a)
+= ALLOCNO_COVER_CLASS_COST (a);
ALLOCNO_MEMORY_COST (parent_a) += ALLOCNO_MEMORY_COST (a);
- ALLOCNO_UPDATED_MEMORY_COST (parent_a)
- += ALLOCNO_UPDATED_MEMORY_COST (a);
}
}
@@ -1789,8 +1787,6 @@ remove_unnecessary_allocnos (void)
ALLOCNO_COVER_CLASS_COST (parent_a)
+= ALLOCNO_COVER_CLASS_COST (a);
ALLOCNO_MEMORY_COST (parent_a) += ALLOCNO_MEMORY_COST (a);
- ALLOCNO_UPDATED_MEMORY_COST (parent_a)
- += ALLOCNO_UPDATED_MEMORY_COST (a);
finish_allocno (a);
}
}
@@ -2349,7 +2345,9 @@ ira_flattening (int max_regno_before_emi
ALLOCNO_LOOP_TREE_NODE (a) = ira_loop_tree_root;
ALLOCNO_REGNO (a) = REGNO (ALLOCNO_REG (a));
ALLOCNO_CAP (a) = NULL;
+ /* Restore updated costs for assignments from reload. */
ALLOCNO_UPDATED_MEMORY_COST (a) = ALLOCNO_MEMORY_COST (a);
+ ALLOCNO_UPDATED_COVER_CLASS_COST (a) = ALLOCNO_COVER_CLASS_COST (a);
if (! ALLOCNO_ASSIGNED_P (a))
ira_free_allocno_updated_costs (a);
ira_assert (ALLOCNO_UPDATED_HARD_REG_COSTS (a) == NULL);
Index: ira.c
===================================================================
--- ira.c (revision 140793)
+++ ira.c (working copy)
@@ -1761,10 +1761,7 @@ ira (FILE *f)
loops_p = ira_build (optimize
&& (flag_ira_algorithm == IRA_ALGORITHM_REGIONAL
|| flag_ira_algorithm == IRA_ALGORITHM_MIXED));
- if (optimize)
- ira_color ();
- else
- ira_fast_allocation ();
+ ira_color ();
ira_max_point_before_emit = ira_max_point;
Index: ira-costs.c
===================================================================
--- ira-costs.c (revision 140793)
+++ ira-costs.c (working copy)
@@ -1405,15 +1405,13 @@ setup_allocno_cover_class_and_costs (voi
mode = ALLOCNO_MODE (a);
cover_class = ira_class_translate[allocno_pref[i]];
ira_assert (allocno_pref[i] == NO_REGS || cover_class != NO_REGS);
- ALLOCNO_MEMORY_COST (a) = ALLOCNO_UPDATED_MEMORY_COST (a)
- = COSTS_OF_ALLOCNO (allocno_costs, i)->mem_cost;
+ ALLOCNO_MEMORY_COST (a) = COSTS_OF_ALLOCNO (allocno_costs, i)->mem_cost;
ira_set_allocno_cover_class (a, cover_class);
if (cover_class == NO_REGS)
continue;
ALLOCNO_AVAILABLE_REGS_NUM (a) = ira_available_class_regs[cover_class];
- ALLOCNO_COVER_CLASS_COST (a)
- = (COSTS_OF_ALLOCNO (allocno_costs, i)
- ->cost[cost_class_nums[allocno_pref[i]]]);
+ ALLOCNO_COVER_CLASS_COST (a) = (COSTS_OF_ALLOCNO (allocno_costs, i)
+ ->cost[cost_class_nums[allocno_pref[i]]]);
if (optimize && ALLOCNO_COVER_CLASS (a) != allocno_pref[i])
{
n = ira_class_hard_regs_num[cover_class];