Re: [RFC] operand_equal_p with valueization

[Richard Biener <rguenther@suse.de>]

On Fri, 22 May 2015, Jan Hubicka wrote:

> > 
> > And no, I'm hesitant to change operand_equal_p too much.  It's
> > very much deep-rooted into GENERIC.
> 
> OK, as another option, i can bring relevant logic from operand_equal_p
> to ipa-icf and separate it into the compare_operand class like I did.
> Use it in ipa-icf-gimple now and we can slowly turn other uses of
> operand_equal into the compare_operand users in middle end.
> 
> I agree that operand_equal is bit crazy code and it does not handle quite few
> things we could do at gimple.  I have nothing against going this direction.
> (after all I do not like touching fold-const much becuase it works on generic,
> gimple and FE non-generic and it is not well specified what it should do)

Yes, I've played with the idea of a GIMPLE specific operand_equal_p 
multiple times but then the changes required to operand_equal_p were
small all the times.  And having one piece of code that does sth is
always good ...

We might turn operand_equal_p to a "worker" (template?) that
operand_equal_p and gimple_operand_equal_p can share (with an extra
flag whether to turn on GIMPLE stuff and/or valueization).  And
then simply provide explicit instantiations for the original
operand_equal_p and a new gimple_operand_equal_p.

Of course we'll only know if we like that when seeing a patch that
does this ;0)

Richard.