Another issue on RS6000 target. Re: One issue with default implementation of zero_call_used_regs

[Richard Sandiford]

Qing Zhao <QING.ZHAO@ORACLE.COM> writes:
>> 
>> Going back to the default hook, I guess one option is:
>> 
>>   rtx zero = CONST0_RTX (reg_raw_mode[regno]);
>>   rtx_insn *insn = emit_insn (gen_rtx_SET (regno_reg_rtx[regno], zero));
>>   if (!valid_insn_p (insn))
>>     sorry (…);
>
> “Sorry” here will tell the user that the implementation on this platform is not valid?

Right.  If we didn't have a default implementation of the target hook,
we would presumably need to issue a sorry () if the user tried to use
the option on a target that didn't define the hook.  The above is a
compromise: we instead make a reasonable attempt to handle the option,
and issue the sorry only if that attempt fails.

Thanks,
Richard

>
> Qing
>> 
>> but with some mechanism to avoid spewing the user with messages
>> for the same problem.
>> 
>> Thanks,
>> Richard