[RFC] Add a new argument to SELECT_CC_MODE

[Richard Earnshaw]

On Tue, 2011-03-22 at 21:00 +0100, Eric Botcazou wrote:
> > Like in the attached patch.
> 
> Sandra expressed an interest for it so I've installed it on the mainline after 
> bootstrapping and regtesting on x86_64-suse-linux.
> 
> 
> 2011-03-22  Eric Botcazou  <ebotcazou@adacore.com>
> 
>         * combine.c (simplify_set): Try harder to find the best CC mode when
>         simplifying a nested COMPARE on the RHS.
> 
> 

So I've always suspected that the way the ARM port handles this is
broken.  I think this now confirms that suspicion.   

Taking a look at the x86 backend the code there looks far more sensible
and more in-line with what I think ARM should be doing.  For a floating
point operation the code is:

  TARGET_IEEE_FP ? CCFPUmode : CCFPmode;

That is, if generating IEEE compliant code, then use non-excepting
comparisions, otherwise use exception raising ones.

R.