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Re: Cleaning up expand optabs code
Richard Sandiford <richard.sandiford@linaro.org> writes:
> Richard Henderson <rth@redhat.com> writes:
>> This is due to a miscommunication between the middle-end and the backend
>> about how many arguments the setmemhi pattern takes.
>>
>> (define_expand "setmemhi"
>> [(parallel [(set (match_operand:BLK 0 "memory_operand" "")
>> (match_operand 2 "const_int_operand" ""))
>> (use (match_operand:HI 1 "const_int_operand" ""))
>> (use (match_operand:HI 3 "const_int_operand" "n"))
>> (clobber (match_scratch:HI 4 ""))
>> (clobber (match_dup 5))])]
>>
>> The match_scratch is counted in .n_operands, which makes the count of
>> operands not equal 4, so we assume 6 operands are necessary. We can
>> fix this for the special case of avr by only assuming 6 operands when
>> there are in fact 6 operands, but of course this could fail just as
>> easily if there were two scratches.
>>
>> All of which suggests that optional arguments to a named optab is a
>> mistake that ought to be rectified.
>>
>> I plan to commit the following after bootstrap and check.
>
> Thanks. I think it needs to be s/!= 4/>= 6/ though, so that
> match_scratches still work when 6 operands really are passed in.
Er, >= 4 even...
Richard