On 19/11/13 17:17, Steven Bosscher wrote:
> On Tue, Nov 19, 2013 at 5:43 PM, Richard Earnshaw wrote:
>> PR 54300 is a problem in regcprop where the compiler sees
>> (parallel [(set (x) (y)
>> (set (y) (x)]) (REG_UNUSED (y))
>>
>> as a single-set insn (since the other operand, y, is not used) and
>> replaces a use of x with a use of y. However, it fails to take into
>> account that y has been clobbered in the insn itself.
>
> Ah, wait. Incorrect use of single_set().
>
> Try
> ------
> }
>
> - set = single_set (insn);
> + set = multiple_sets (insn) ? NULL_RTX : single_set (insn);
> extract_insn (insn);
> if (! constrain_operands (1))
> fatal_insn_not_found (insn);
> preprocess_constraints ();
> ------
>
> Ciao!
> Steven
>
That won't handle
parallel [ (set (x) (y))
(clobber (y))]
R.
