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lra: consider clobbers when selecting hard_regno to spill

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The idea behind the rclass loop in spill_hard_reg_in_range() seems to
be: find a hard_regno, which in general conflicts with reload regno,
but does not do so between `from` and `to`, and then do the live range
splitting based on this information. To check the absence of conflicts,
we make use of insn_bitmap, which does not contain insns which clobber
the hard_regno.

gcc/ChangeLog:

2018-07-30  Ilya Leoshkevich  <iii@linux.ibm.com>

        PR target/86547
	* lra-constraints.c (spill_hard_reg_in_range): When selecting the
	hard_regno, make sure no insn between `from` and `to` clobbers it.

From-SVN: r263063
This commit is contained in:
Ilya Leoshkevich 2018-07-30 08:30:06 +00:00 • committed by Andreas Krebbel
parent 4cdfee3f20
commit dc843a8597
2 changed files with 19 additions and 3 deletions
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6
gcc/ChangeLog
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@ -1,3 +1,9 @@
2018-07-30 Ilya Leoshkevich <iii@linux.ibm.com>
PR target/86547
* lra-constraints.c (spill_hard_reg_in_range): When selecting the
hard_regno, make sure no insn between `from` and `to` clobbers it.
2018-07-30 Cesar Philippidis <cesar@codesourcery.com>
Tom de Vries <tdevries@suse.de>

16
gcc/lra-constraints.c
View file

@ -5722,9 +5722,19 @@ spill_hard_reg_in_range (int regno, enum reg_class rclass, rtx_insn *from, rtx_i
|| TEST_HARD_REG_BIT (ignore, 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;
{
lra_insn_recog_data_t id = lra_insn_recog_data[uid = INSN_UID (insn)];
struct lra_static_insn_data *static_id = id->insn_static_data;
struct lra_insn_reg *reg;
if (bitmap_bit_p (&lra_reg_info[hard_regno].insn_bitmap, uid))
break;
for (reg = static_id->hard_regs; reg != NULL; reg = reg->next)
if (reg->regno == hard_regno)
break;
if (reg != NULL)
break;
}
if (insn != NEXT_INSN (to))
continue;
if (split_reg (TRUE, hard_regno, from, NULL, to))