The following patch fixes
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65710
The patch was bootstrapped and tested on x86/x86-64, ppc64, and aarch64.
The patch does not contain the test as it is too big. If it is reduced,
the test can be committed.
Committed as rev. 221956.
I am also submitting analogous patch to gcc-4.9 branch.
2015-04-09 Vladimir Makarov <vmaka...@redhat.com>
PR target/65710
* lra-int.h (lra_bad_spill_regno_start): New.
* lra.c (lra_bad_spill_regno_start): New.
(lra): Set up lra_bad_spill_regno_start. Set up
lra_constraint_new_regno_start unconditionally.
* lra-assigns.c (spill_for): Use lra_bad_spill_regno_start for
spill preferences.
Index: lra-assigns.c
===================================================================
--- lra-assigns.c (revision 221949)
+++ lra-assigns.c (working copy)
@@ -910,6 +910,7 @@ spill_for (int regno, bitmap spilled_pse
enum reg_class rclass;
unsigned int spill_regno, reload_regno, uid;
int insn_pseudos_num, best_insn_pseudos_num;
+ int bad_spills_num, smallest_bad_spills_num;
lra_live_range_t r;
bitmap_iterator bi;
@@ -928,6 +929,7 @@ spill_for (int regno, bitmap spilled_pse
best_hard_regno = -1;
best_cost = INT_MAX;
best_insn_pseudos_num = INT_MAX;
+ smallest_bad_spills_num = INT_MAX;
rclass_size = ira_class_hard_regs_num[rclass];
mode = PSEUDO_REGNO_MODE (regno);
/* Invalidate try_hard_reg_pseudos elements. */
@@ -958,6 +960,7 @@ spill_for (int regno, bitmap spilled_pse
&& ! bitmap_bit_p (&lra_optional_reload_pseudos, spill_regno)))
goto fail;
insn_pseudos_num = 0;
+ bad_spills_num = 0;
if (lra_dump_file != NULL)
fprintf (lra_dump_file, " Trying %d:", hard_regno);
sparseset_clear (live_range_reload_inheritance_pseudos);
@@ -965,6 +968,8 @@ spill_for (int regno, bitmap spilled_pse
{
if (bitmap_bit_p (&insn_conflict_pseudos, spill_regno))
insn_pseudos_num++;
+ if (spill_regno >= (unsigned int) lra_bad_spill_regno_start)
+ bad_spills_num++;
for (r = lra_reg_info[spill_regno].live_ranges;
r != NULL;
r = r->next)
@@ -1035,7 +1040,9 @@ spill_for (int regno, bitmap spilled_pse
}
if (best_insn_pseudos_num > insn_pseudos_num
|| (best_insn_pseudos_num == insn_pseudos_num
- && best_cost > cost))
+ && (bad_spills_num < smallest_bad_spills_num
+ || (bad_spills_num == smallest_bad_spills_num
+ && best_cost > cost))))
{
best_insn_pseudos_num = insn_pseudos_num;
best_cost = cost;
Index: lra.c
===================================================================
--- lra.c (revision 221949)
+++ lra.c (working copy)
@@ -2180,6 +2180,10 @@ int lra_new_regno_start;
/* Start of reload pseudo regnos before the new spill pass. */
int lra_constraint_new_regno_start;
+/* Avoid spilling pseudos with regno more than the following value if
+ it is possible. */
+int lra_bad_spill_regno_start;
+
/* Inheritance pseudo regnos before the new spill pass. */
bitmap_head lra_inheritance_pseudos;
@@ -2269,6 +2273,7 @@ lra (FILE *f)
permit changing reg classes for pseudos created by this
simplification. */
lra_constraint_new_regno_start = lra_new_regno_start = max_reg_num ();
+ lra_bad_spill_regno_start = INT_MAX;
remove_scratches ();
scratch_p = lra_constraint_new_regno_start != max_reg_num ();
@@ -2406,12 +2411,14 @@ lra (FILE *f)
/* Assignment of stack slots changes elimination offsets for
some eliminations. So update the offsets here. */
lra_eliminate (false, false);
- /* After switching off inheritance and rematerialization passes,
- don't forget reload pseudos after spilling sub-pass to avoid
- LRA cycling in some complicated cases. */
- if (lra_inheritance_iter <= LRA_MAX_INHERITANCE_PASSES
- || lra_rematerialization_iter <= LRA_MAX_REMATERIALIZATION_PASSES)
- lra_constraint_new_regno_start = max_reg_num ();
+ lra_constraint_new_regno_start = max_reg_num ();
+ if (lra_bad_spill_regno_start == INT_MAX
+ && lra_inheritance_iter > LRA_MAX_INHERITANCE_PASSES
+ && lra_rematerialization_iter > LRA_MAX_REMATERIALIZATION_PASSES)
+ /* After switching off inheritance and rematerialization
+ passes, avoid spilling reload pseudos will be created to
+ prevent LRA cycling in some complicated cases. */
+ lra_bad_spill_regno_start = lra_constraint_new_regno_start;
lra_assignment_iter_after_spill = 0;
}
restore_scratches ();
Index: lra-int.h
===================================================================
--- lra-int.h (revision 221949)
+++ lra-int.h (working copy)
@@ -333,6 +333,7 @@ extern void lra_register_new_scratch_op
extern int lra_new_regno_start;
extern int lra_constraint_new_regno_start;
+extern int lra_bad_spill_regno_start;
extern bitmap_head lra_inheritance_pseudos;
extern bitmap_head lra_split_regs;
extern bitmap_head lra_subreg_reload_pseudos;
