On 11/17/2015 10:08 AM, Kyrill Tkachov wrote:
Yes, I had considered that as well. It should be equivalent. I didn't
use !reg_used_between_p because I thought
it'd be more expensive than checking reg_overlap_mentioned_p since we
must iterate over a number of instructions
and call reg_overlap_mentioned_p on each one. But I suppose this case is
rare enough that it wouldn't make any
measurable difference.
Would you prefer to use !reg_used_between_p here?
I would but apparently it doesn't work, so that's kind of neither here
nor there.
The added comment could lead to some confusion since it's placed in
front of an existing if statement that also tests a different
condition. Also, if we go with your fix,
+ || !reg_overlap_mentioned_p (tmp_reg, SET_SRC (PATTERN
(cand->insn))))
Shouldn't this really be !rtx_equal_p?
Maybe, will it behave the right way if the two regs have different modes
or when subregs are involved?
It would return false, in which case we'll conservatively fail here. I
think that's desirable?
Bernd
