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Re: [RFC] Curious REG_EQUAL note for multiplication
Kaz Kojima wrote:
> Dave Korn <email@example.com> wrote:
>> Tagging the correct note onto a nop-move sequence was suggested at the time
>> as a possible solution. I think I tried it and it didn't work first time and
>> I never had a chance to track it any further at the time.
> I've tried to add a (set DIreg DIreg) insn at expand_mult_const
> associated with the note, but it can't survive to the CSE phase.
Urgh. No real surprise I suppose. If you wanted to try an experiment, you
might get it to be preserved by marking it volatile, but it wouldn't be a good
production solution to place a scheduling barrier at the end of every
multi-word register manipulation sequence!