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Re: [PATCH] register CALL_INSN_FUNCTION_USAGE in find_all_hard_reg_sets


Tom de Vries <Tom_deVries@mentor.com> writes:
> On 16/04/14 12:28, Richard Sandiford wrote:
>>> > This patch introduces a hook that specifies which registers are implicitly 
>>> > clobbered by a call, not including the registers that are clobbered in the 
>>> > called function, and then uses that hook to add those registers to 
>>> > CALL_INSN_FUNCTION_USAGE.
>
>> I don't think a new hook is needed.
>
> Richard,
>
> the hook enables us to determine whether a target supplies the information
> provided by the hook. If the target does not provide this information, the
> fuse-caller-save optimization is possibly not safe.
>
> How do you propose to handle this without this hook?

Maybe we should just have a bool field in the target structure to say
whether -fuse-caller-save is supported, a bit like delay_sched2.

Thanks,
Richard


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