[RTL, ColdFire 24/63] Add support for a MODE_INDEX_REG_CLASS macro

[Richard Sandiford]

Jeffrey Law <law@redhat.com> writes:
>> My concern about efficiency still stands though.  Concretely,
>> your patch is going to mean that the MIPS port does (29 modes x
>> 188 regs =) 5452 legitimate address checks at startup, all of
>> which will be false.  The figure for PowerPC is (38 modes x 114 regs =)
>> 4332 checks and the figure for ia64 is (40 modes * 334 regs =) 13360 checks.
>> (I realise that ia64 is one of those targets where you expect the compiler
>> to be slower, but still. ;))  As the patch stands, it will also create
>> new garbage addresses for each check.  I think at the very least you
>> should:
>> 
>>   - create one address and use it for all checks, changing parts of
>>     it as appropriate
> Definitely.  Please go ahead and do this.

Sorry, but I still strongly believe you're leading us in the
wrong direction here.  I suggest we leave it for someone else
with less strong feelings.  And...

> I was merely showing a quick proof of concept, it wasn't necessarily
> meant to go into the tree as-is, but instead show you the way to 
> getting this problem cleanly resolved.

...with respect Jeff, I didn't need you to tell me how the
double_reg_address_ok thing should be implemented.  I was resisting
doing it because I disagreed with it, not because I didn't understand
the concept.

Richard