===================================================================
@@ -1,3 +1,25 @@
+2018-03-13 Vladimir Makarov <vmakarov@redhat.com>
+
+ PR target/83712
+ * lra-assigns.c (find_all_spills_for): Ignore uninteresting
+ pseudos.
+ (assign_by_spills): Return a flag of reload assignment failure.
+ Do not process the reload assignment failures. Do not spill other
+ reload pseudos if they has the same reg class. Update n if
+ necessary.
+ (lra_assign): Add a return arg. Set up from the result of
+ assign_by_spills call.
+ (find_reload_regno_insns, lra_split_hard_reg_for): New functions.
+ * lra-constraints.c (split_reg): Add a new arg. Use it instead of
+ usage_insns if it is not NULL.
+ (spill_hard_reg_in_range): New function.
+ (split_if_necessary, inherit_in_ebb): Pass a new arg to split_reg.
+ * lra-int.h (spill_hard_reg_in_range, lra_split_hard_reg_for): New
+ function prototypes.
+ (lra_assign): Change prototype.
+ * lra.c (lra): Add code to deal with fails by splitting hard reg
+ live ranges.
+
2018-03-01 Palmer Dabbelt <palmer@sifive.com>
* config/riscv/riscv.opt (mrelax): New option.
===================================================================
@@ -1339,24 +1339,33 @@ find_all_spills_for (int regno)
r2 = r2->start_next)
{
if (live_pseudos_reg_renumber[r2->regno] >= 0
- && rclass_intersect_p[regno_allocno_class_array[r2->regno]])
+ && ! sparseset_bit_p (live_range_hard_reg_pseudos, r2->regno)
+ && rclass_intersect_p[regno_allocno_class_array[r2->regno]]
+ && ((int) r2->regno < lra_constraint_new_regno_start
+ || bitmap_bit_p (&lra_inheritance_pseudos, r2->regno)
+ || bitmap_bit_p (&lra_split_regs, r2->regno)
+ || bitmap_bit_p (&lra_optional_reload_pseudos, r2->regno)
+ /* There is no sense to consider another reload
+ pseudo if it has the same class. */
+ || regno_allocno_class_array[r2->regno] != rclass))
sparseset_set_bit (live_range_hard_reg_pseudos, r2->regno);
}
}
}
}
-/* Assign hard registers to reload pseudos and other pseudos. */
-static void
+/* Assign hard registers to reload pseudos and other pseudos. Return
+ true if we was not able to assign hard registers to all reload
+ pseudos. */
+static bool
assign_by_spills (void)
{
- int i, n, nfails, iter, regno, hard_regno, cost;
+ int i, n, nfails, iter, regno, regno2, hard_regno, cost;
rtx restore_rtx;
- rtx_insn *insn;
bitmap_head changed_insns, do_not_assign_nonreload_pseudos;
unsigned int u, conflict_regno;
bitmap_iterator bi;
- bool reload_p;
+ bool reload_p, fails_p = false;
int max_regno = max_reg_num ();
for (n = 0, i = lra_constraint_new_regno_start; i < max_regno; i++)
@@ -1399,8 +1408,13 @@ assign_by_spills (void)
hard_regno = spill_for (regno, &all_spilled_pseudos, iter == 1);
if (hard_regno < 0)
{
- if (reload_p)
+ if (reload_p) {
+ /* Put unassigned reload pseudo first in the
+ array. */
+ regno2 = sorted_pseudos[nfails];
sorted_pseudos[nfails++] = regno;
+ sorted_pseudos[i] = regno2;
+ }
}
else
{
@@ -1415,61 +1429,9 @@ assign_by_spills (void)
bitmap_set_bit (&changed_pseudo_bitmap, regno);
}
}
- if (nfails == 0)
- break;
- if (iter > 0)
+ if (nfails == 0 || iter > 0)
{
- /* We did not assign hard regs to reload pseudos after two iterations.
- Either it's an asm and something is wrong with the constraints, or
- we have run out of spill registers; error out in either case. */
- bool asm_p = false;
- bitmap_head failed_reload_insns;
-
- bitmap_initialize (&failed_reload_insns, ®_obstack);
- for (i = 0; i < nfails; i++)
- {
- regno = sorted_pseudos[i];
- bitmap_ior_into (&failed_reload_insns,
- &lra_reg_info[regno].insn_bitmap);
- /* Assign an arbitrary hard register of regno class to
- avoid further trouble with this insn. */
- bitmap_clear_bit (&all_spilled_pseudos, regno);
- assign_hard_regno
- (ira_class_hard_regs[regno_allocno_class_array[regno]][0],
- regno);
- }
- EXECUTE_IF_SET_IN_BITMAP (&failed_reload_insns, 0, u, bi)
- {
- insn = lra_insn_recog_data[u]->insn;
- if (asm_noperands (PATTERN (insn)) >= 0)
- {
- asm_p = true;
- error_for_asm (insn,
- "%<asm%> operand has impossible constraints");
- /* Avoid further trouble with this insn.
- For asm goto, instead of fixing up all the edges
- just clear the template and clear input operands
- (asm goto doesn't have any output operands). */
- if (JUMP_P (insn))
- {
- rtx asm_op = extract_asm_operands (PATTERN (insn));
- ASM_OPERANDS_TEMPLATE (asm_op) = ggc_strdup ("");
- ASM_OPERANDS_INPUT_VEC (asm_op) = rtvec_alloc (0);
- ASM_OPERANDS_INPUT_CONSTRAINT_VEC (asm_op) = rtvec_alloc (0);
- lra_update_insn_regno_info (insn);
- }
- else
- {
- PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
- lra_set_insn_deleted (insn);
- }
- }
- else if (!asm_p)
- {
- error ("unable to find a register to spill");
- fatal_insn ("this is the insn:", insn);
- }
- }
+ fails_p = nfails != 0;
break;
}
/* This is a very rare event. We can not assign a hard register
@@ -1518,7 +1480,8 @@ assign_by_spills (void)
update_lives (conflict_regno, true);
lra_setup_reg_renumber (conflict_regno, -1, false);
}
- n = nfails;
+ if (n < nfails)
+ n = nfails;
}
improve_inheritance (&changed_pseudo_bitmap);
bitmap_clear (&non_reload_pseudos);
@@ -1604,9 +1567,9 @@ assign_by_spills (void)
bitmap_clear (&best_spill_pseudos_bitmap);
bitmap_clear (&spill_pseudos_bitmap);
bitmap_clear (&insn_conflict_pseudos);
+ return fails_p;
}
-
/* Entry function to assign hard registers to new reload pseudos
starting with LRA_CONSTRAINT_NEW_REGNO_START (by possible spilling
of old pseudos) and possibly to the old pseudos. The function adds
@@ -1615,9 +1578,10 @@ assign_by_spills (void)
changed allocation.
Return true if we did not spill any non-reload and non-inheritance
- pseudos. */
+ pseudos. Set up FAILS_P if we failed to assign hard registers to
+ all reload pseudos. */
bool
-lra_assign (void)
+lra_assign (bool &fails_p)
{
int i;
unsigned int u;
@@ -1661,7 +1625,7 @@ lra_assign (void)
/* Setup insns to process on the next constraint pass. */
bitmap_initialize (&changed_pseudo_bitmap, ®_obstack);
init_live_reload_and_inheritance_pseudos ();
- assign_by_spills ();
+ fails_p = assign_by_spills ();
finish_live_reload_and_inheritance_pseudos ();
bitmap_ior_into (&changed_pseudo_bitmap, &all_spilled_pseudos);
no_spills_p = true;
@@ -1707,3 +1671,139 @@ lra_assign (void)
return no_spills_p;
}
+/* Find start and finish insns for reload pseudo REGNO. Return true
+ if we managed to find the expected insns. Return false,
+ otherwise. */
+static bool
+find_reload_regno_insns (int regno, rtx_insn * &start, rtx_insn * &finish)
+{
+ unsigned int uid;
+ bitmap_iterator bi;
+ int n = 0;
+ rtx_insn *prev_insn, *next_insn;
+ rtx_insn *start_insn = NULL, *first_insn = NULL, *second_insn = NULL;
+
+ EXECUTE_IF_SET_IN_BITMAP (&lra_reg_info[regno].insn_bitmap, 0, uid, bi)
+ {
+ if (start_insn == NULL)
+ start_insn = lra_insn_recog_data[uid]->insn;
+ n++;
+ }
+ /* For reload pseudo we should have at most 3 insns referring for it:
+ input/output reload insns and the original insn. */
+ if (n > 3)
+ return false;
+ if (n > 1)
+ {
+ for (prev_insn = PREV_INSN (start_insn),
+ next_insn = NEXT_INSN (start_insn);
+ n != 1 && (prev_insn != NULL || next_insn != NULL); )
+ {
+ if (prev_insn != NULL && first_insn == NULL)
+ {
+ if (! bitmap_bit_p (&lra_reg_info[regno].insn_bitmap,
+ INSN_UID (prev_insn)))
+ prev_insn = PREV_INSN (prev_insn);
+ else
+ {
+ first_insn = prev_insn;
+ n--;
+ }
+ }
+ if (next_insn != NULL && second_insn == NULL)
+ {
+ if (! bitmap_bit_p (&lra_reg_info[regno].insn_bitmap,
+ INSN_UID (next_insn)))
+ next_insn = NEXT_INSN (next_insn);
+ else
+ {
+ second_insn = next_insn;
+ n--;
+ }
+ }
+ }
+ if (n > 1)
+ return false;
+ }
+ start = first_insn != NULL ? first_insn : start_insn;
+ finish = second_insn != NULL ? second_insn : start_insn;
+ return true;
+}
+
+/* Process reload pseudos which did not get a hard reg, split a hard
+ reg live range in live range of a reload pseudo, and then return
+ TRUE. If we did not split a hard reg live range, report an error,
+ and return FALSE. */
+bool
+lra_split_hard_reg_for (void)
+{
+ int i, regno, n;
+ rtx_insn *insn, *first, *last;
+ unsigned int u;
+ bitmap_iterator bi;
+ int max_regno = max_reg_num ();
+ /* We did not assign hard regs to reload pseudos after two
+ iterations. Either it's an asm and something is wrong with the
+ constraints, or we have run out of spill registers; error out in
+ either case. */
+ bool asm_p = false;
+ bitmap_head failed_reload_insns;
+
+ if (lra_dump_file != NULL)
+ fprintf (lra_dump_file,
+ "\n****** Splitting a hard reg after assignment #%d: ******\n\n",
+ lra_assignment_iter);
+ for (n = 0, i = lra_constraint_new_regno_start; i < max_regno; i++)
+ if (reg_renumber[i] < 0 && lra_reg_info[i].nrefs != 0
+ && regno_allocno_class_array[i] != NO_REGS
+ && ! bitmap_bit_p (&non_reload_pseudos, i))
+ {
+ sorted_pseudos[n++] = i;
+ if (! find_reload_regno_insns (i, first, last))
+ continue;
+ if (spill_hard_reg_in_range (i, regno_allocno_class_array[i],
+ first, last))
+ return true;
+ }
+ bitmap_initialize (&failed_reload_insns, ®_obstack);
+ for (i = 0; i < n; i++)
+ {
+ regno = sorted_pseudos[i];
+ bitmap_ior_into (&failed_reload_insns,
+ &lra_reg_info[regno].insn_bitmap);
+ lra_setup_reg_renumber (regno, ira_class_hard_regs[regno_allocno_class_array[regno]][0], false);
+ }
+ EXECUTE_IF_SET_IN_BITMAP (&failed_reload_insns, 0, u, bi)
+ {
+ insn = lra_insn_recog_data[u]->insn;
+ if (asm_noperands (PATTERN (insn)) >= 0)
+ {
+ asm_p = true;
+ error_for_asm (insn,
+ "%<asm%> operand has impossible constraints");
+ /* Avoid further trouble with this insn.
+ For asm goto, instead of fixing up all the edges
+ just clear the template and clear input operands
+ (asm goto doesn't have any output operands). */
+ if (JUMP_P (insn))
+ {
+ rtx asm_op = extract_asm_operands (PATTERN (insn));
+ ASM_OPERANDS_TEMPLATE (asm_op) = ggc_strdup ("");
+ ASM_OPERANDS_INPUT_VEC (asm_op) = rtvec_alloc (0);
+ ASM_OPERANDS_INPUT_CONSTRAINT_VEC (asm_op) = rtvec_alloc (0);
+ lra_update_insn_regno_info (insn);
+ }
+ else
+ {
+ PATTERN (insn) = gen_rtx_USE (VOIDmode, const0_rtx);
+ lra_set_insn_deleted (insn);
+ }
+ }
+ else if (!asm_p)
+ {
+ error ("unable to find a register to spill");
+ fatal_insn ("this is the insn:", insn);
+ }
+ }
+ return false;
+}
===================================================================
@@ -2461,38 +2461,54 @@ lra (FILE *f)
}
if (live_p)
lra_clear_live_ranges ();
- /* We need live ranges for lra_assign -- so build them. But
- don't remove dead insns or change global live info as we
- can undo inheritance transformations after inheritance
- pseudo assigning. */
- lra_create_live_ranges (true, false);
- live_p = true;
- /* If we don't spill non-reload and non-inheritance pseudos,
- there is no sense to run memory-memory move coalescing.
- If inheritance pseudos were spilled, the memory-memory
- moves involving them will be removed by pass undoing
- inheritance. */
- if (lra_simple_p)
- lra_assign ();
- else
+ bool fails_p;
+ do
{
- bool spill_p = !lra_assign ();
-
- if (lra_undo_inheritance ())
- live_p = false;
- if (spill_p)
+ /* We need live ranges for lra_assign -- so build them.
+ But don't remove dead insns or change global live
+ info as we can undo inheritance transformations after
+ inheritance pseudo assigning. */
+ lra_create_live_ranges (true, false);
+ live_p = true;
+ /* If we don't spill non-reload and non-inheritance
+ pseudos, there is no sense to run memory-memory move
+ coalescing. If inheritance pseudos were spilled, the
+ memory-memory moves involving them will be removed by
+ pass undoing inheritance. */
+ if (lra_simple_p)
+ lra_assign (fails_p);
+ else
{
- if (! live_p)
+ bool spill_p = !lra_assign (fails_p);
+
+ if (lra_undo_inheritance ())
+ live_p = false;
+ if (spill_p && ! fails_p)
{
- lra_create_live_ranges (true, true);
- live_p = true;
+ if (! live_p)
+ {
+ lra_create_live_ranges (true, true);
+ live_p = true;
+ }
+ if (lra_coalesce ())
+ live_p = false;
}
- if (lra_coalesce ())
- live_p = false;
+ if (! live_p)
+ lra_clear_live_ranges ();
+ }
+ if (fails_p)
+ {
+ /* It is a very rare case. It is the last hope to
+ split a hard regno live range for a reload
+ pseudo. */
+ if (live_p)
+ lra_clear_live_ranges ();
+ live_p = false;
+ if (! lra_split_hard_reg_for ())
+ break;
}
- if (! live_p)
- lra_clear_live_ranges ();
}
+ while (fails_p);
}
/* Don't clear optional reloads bitmap until all constraints are
satisfied as we need to differ them from regular reloads. */
===================================================================
@@ -5458,7 +5458,8 @@ lra_copy_reg_equiv (unsigned int new_reg
/* Do split transformations for insn INSN, which defines or uses
ORIGINAL_REGNO. NEXT_USAGE_INSNS specifies which instruction in
the EBB next uses ORIGINAL_REGNO; it has the same form as the
- "insns" field of usage_insns.
+ "insns" field of usage_insns. If TO is not NULL, we don't use
+ usage_insns, we put restore insns after TO insn.
The transformations look like:
@@ -5480,7 +5481,7 @@ lra_copy_reg_equiv (unsigned int new_reg
transformation. */
static bool
split_reg (bool before_p, int original_regno, rtx_insn *insn,
- rtx next_usage_insns)
+ rtx next_usage_insns, rtx_insn *to)
{
enum reg_class rclass;
rtx original_reg;
@@ -5613,29 +5614,37 @@ split_reg (bool before_p, int original_r
if (!HARD_REGISTER_NUM_P (original_regno)
&& mode == PSEUDO_REGNO_MODE (original_regno))
lra_copy_reg_equiv (new_regno, original_regno);
- after_p = usage_insns[original_regno].after_p;
lra_reg_info[new_regno].restore_rtx = regno_reg_rtx[original_regno];
bitmap_set_bit (&check_only_regs, new_regno);
bitmap_set_bit (&check_only_regs, original_regno);
bitmap_set_bit (&lra_split_regs, new_regno);
- for (;;)
+ if (to != NULL)
{
- if (GET_CODE (next_usage_insns) != INSN_LIST)
- {
- usage_insn = next_usage_insns;
- break;
- }
- usage_insn = XEXP (next_usage_insns, 0);
- lra_assert (DEBUG_INSN_P (usage_insn));
- next_usage_insns = XEXP (next_usage_insns, 1);
- lra_substitute_pseudo (&usage_insn, original_regno, new_reg, false,
- true);
- lra_update_insn_regno_info (as_a <rtx_insn *> (usage_insn));
- if (lra_dump_file != NULL)
+ usage_insn = to;
+ after_p = TRUE;
+ }
+ else
+ {
+ after_p = usage_insns[original_regno].after_p;
+ for (;;)
{
- fprintf (lra_dump_file, " Split reuse change %d->%d:\n",
- original_regno, new_regno);
- dump_insn_slim (lra_dump_file, as_a <rtx_insn *> (usage_insn));
+ if (GET_CODE (next_usage_insns) != INSN_LIST)
+ {
+ usage_insn = next_usage_insns;
+ break;
+ }
+ usage_insn = XEXP (next_usage_insns, 0);
+ lra_assert (DEBUG_INSN_P (usage_insn));
+ next_usage_insns = XEXP (next_usage_insns, 1);
+ lra_substitute_pseudo (&usage_insn, original_regno, new_reg, false,
+ true);
+ lra_update_insn_regno_info (as_a <rtx_insn *> (usage_insn));
+ if (lra_dump_file != NULL)
+ {
+ fprintf (lra_dump_file, " Split reuse change %d->%d:\n",
+ original_regno, new_regno);
+ dump_insn_slim (lra_dump_file, as_a <rtx_insn *> (usage_insn));
+ }
}
}
lra_assert (NOTE_P (usage_insn) || NONDEBUG_INSN_P (usage_insn));
@@ -5662,6 +5671,35 @@ split_reg (bool before_p, int original_r
return true;
}
+/* Split a hard reg for reload pseudo REGNO having RCLASS and living
+ in the range [FROM, TO]. Return true if did a split. Otherwise,
+ return false. */
+bool
+spill_hard_reg_in_range (int regno, enum reg_class rclass, rtx_insn *from, rtx_insn *to)
+{
+ int i, hard_regno;
+ int rclass_size;
+ rtx_insn *insn;
+
+ lra_assert (from != NULL && to != NULL);
+ rclass_size = ira_class_hard_regs_num[rclass];
+ for (i = 0; i < rclass_size; i++)
+ {
+ hard_regno = ira_class_hard_regs[rclass][i];
+ if (! TEST_HARD_REG_BIT (lra_reg_info[regno].conflict_hard_regs, hard_regno))
+ continue;
+ for (insn = from; insn != NEXT_INSN (to); insn = NEXT_INSN (insn))
+ if (bitmap_bit_p (&lra_reg_info[hard_regno].insn_bitmap,
+ INSN_UID (insn)))
+ break;
+ if (insn != NEXT_INSN (to))
+ continue;
+ if (split_reg (TRUE, hard_regno, from, NULL, to))
+ return true;
+ }
+ return false;
+}
+
/* Recognize that we need a split transformation for insn INSN, which
defines or uses REGNO in its insn biggest MODE (we use it only if
REGNO is a hard register). POTENTIAL_RELOAD_HARD_REGS contains
@@ -5689,7 +5727,7 @@ split_if_necessary (int regno, machine_m
|| (GET_CODE (next_usage_insns) == INSN_LIST
&& (INSN_UID (XEXP (next_usage_insns, 0)) < max_uid)))
&& need_for_split_p (potential_reload_hard_regs, regno + i)
- && split_reg (before_p, regno + i, insn, next_usage_insns))
+ && split_reg (before_p, regno + i, insn, next_usage_insns, NULL))
res = true;
return res;
}
@@ -6467,7 +6505,7 @@ inherit_in_ebb (rtx_insn *head, rtx_insn
head_p = false;
}
if (split_reg (false, j, bb_note (curr_bb),
- next_usage_insns))
+ next_usage_insns, NULL))
change_p = true;
}
usage_insns[j].check = 0;
===================================================================
@@ -356,6 +356,7 @@ extern bool lra_constrain_insn (rtx_insn
extern bool lra_constraints (bool);
extern void lra_constraints_init (void);
extern void lra_constraints_finish (void);
+extern bool spill_hard_reg_in_range (int, enum reg_class, rtx_insn *, rtx_insn *);
extern void lra_inheritance (void);
extern bool lra_undo_inheritance (void);
@@ -389,8 +390,8 @@ extern void lra_setup_reload_pseudo_pref
extern int lra_assignment_iter;
extern int lra_assignment_iter_after_spill;
extern void lra_setup_reg_renumber (int, int, bool);
-extern bool lra_assign (void);
-
+extern bool lra_assign (bool &);
+extern bool lra_split_hard_reg_for (void);
/* lra-coalesce.c: */