lra: consider clobbers when selecting hard_regno to spill

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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5da437875282fe4674ce302187ce89a2e51a7d23..c635f776e34e0753c8ca5f39c541c87a3bcb83d7 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -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>
 

diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 7eeec767445bb1caa7dcac5239bdde1efd42a8b3..6d4042ebdc228d93136214687cad4da0e5a1e169 100644 (file)
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -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))