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Re: Scheduling and inserting NOPs
Boris Boesler <firstname.lastname@example.org> writes:
> Now I need a pass to insert the missing NOPs. The approach Ian
> mentioned with the DFA-simulator does not work, because the simulator
> detects structural hardware hazards only (see http://www.nabble.com/Re
> %3A-Question-of-the-DFA-scheduler-p603486.html), which can not occur
> in my processor. Or did the DFA change?
I didn't suggest using the DFA simulator. I agree that that won't
work. What I suggested was to insert the NOPs in the
TARGET_ASM_FUNCTION_PROLOGUE hook. This is not a scheduling hook. It
is target specific code that is run immediately before the assembly
instructions are generated.
It seems to me that I keep saying the same thing, and you keep saying
that it won't work without explaining why. I won't reply again.
Andrew's suggestion of using TARGET_MACHINE_DEPENDENT_REORG can also
work. I don't like that approach as much in practice because it
doesn't work in conjunction with delay slots. On some machines delay
slots are a good way to model VLIW semantics, in which instructions
can execute in parallel.