VARRAY_GROW (may_not_optimize, nregs);
}
- validate_change (v->insn, &SET_DEST (set), dest_reg, 1);
- validate_change (next->insn, next->location, add_val, 1);
- if (! apply_change_group ())
+ if (! validate_change (next->insn, next->location, add_val, 0))
{
vp = &v->next_iv;
continue;
}
+
+ /* Here we can try to eliminate the increment by combining
+ it into the uses. */
+
+ /* Set last_use_insn so that we can check against it. */
+
+ for (last_use_insn = v->insn, p = NEXT_INSN (v->insn);
+ p != next->insn;
+ p = next_insn_in_loop (p, scan_start, end, loop_top))
+ {
+ rtx note;
+
+ if (GET_RTX_CLASS (GET_CODE (p)) != 'i')
+ continue;
+ if (reg_mentioned_p (old_reg, PATTERN (p)))
+ {
+ last_use_insn = p;
+ }
+ }
+
+ /* If we can't get the LUIDs for the insns, we can't
+ calculate the lifetime. This is likely from unrolling
+ of an inner loop, so there is little point in making this
+ a DEST_REG giv anyways. */
+ if (INSN_UID (v->insn) >= max_uid_for_loop
+ || INSN_UID (last_use_insn) >= max_uid_for_loop
+ || ! validate_change (v->insn, &SET_DEST (set), dest_reg, 0))
+ {
+ /* Change the increment at NEXT back to what it was. */
+ if (! validate_change (next->insn, next->location,
+ next->add_val, 0))
+ abort ();
+ vp = &v->next_iv;
+ continue;
+ }
next->add_val = add_val;
v->dest_reg = dest_reg;
v->giv_type = DEST_REG;