A new patch for floating point conditional mov on PPo
Fri Jun 12 09:17:00 GMT 1998
> > That is not a problem, see above.
> Yes it is a problem.
> Consider a smarter notice_update_cc which realizes that integer
> conditional moves don't clobber cc0 and the following bit of code:
> int a;
> int b;
> int c;
> int d;
> double e;
> double f;
> if (a < b)
> d = c;
> if (a < b)
> f = e;
> In this example the second comparison which you are depending on to
> muck cc0 will be eliminated. It is probably safer to leave the
> integer comparison patterns alone and muck cc0 as part of outputting
> the FP conditional move.
> A patch has been applied which prevents bad code from being generated
> in the case of a FP conditional move based signed integer comparisons
> so I believe that you have time to refine your patch if you're interested
> in pursuing it.
> BTW, I'll probably be supplying a patch to make notice_update_cc0 smarter
> about integer conditional moves so it is kind of a real concern. :-)
The current notice_update_cc0 works with my current patch. If
there is a change in notice_update_cc0, I think I may find a way
to accommodate it.
BTW, I also want to fix FP comparison for conditional moves. But
we have to do it one by one. Let's get over with signed int
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