Supporting FP cmp lib routines

[Richard Henderson]

On 09/14/2009 06:59 AM, Mohamed Shafi wrote:
> Is there a way to let GCC know that the result for FP compare
> are stored in the Status Register so that GCC generates directly a
> jump operation? How can i implement this?

There is no way to do this via the standard libcall sequence.

In order to implement this, you'll want to build the function
calls yourself, directly from the cbranch expanders.  Have a
look at alpha_emit_xfloating_libcall for ideas.

You'll want to make sure that that your status register is set
up as the return value of the call pattern, i.e.

   (set (reg:CC status-reg)
        (call:CC (mem (symbol_ref "fp-compare-routine"))))


That should be about all you need to get things working.


r~