ppc64 floating point usage [was Re: PPC64 Compiler bug !!]

[Michael S. Zick]

On Friday 13 June 2003 04:02 pm, linas@austin.ibm.com wrote:
> On Fri, Jun 13, 2003 at 04:09:06PM -0400, David Edelsohn wrote:
>
> Bird in hand vs. two in the bush.  We have Alan Modra's patch now, we
> don't have an acceptable -mno-implicit-float patch.
>
> There is concern that Alan's patch will negatively impact performance
> of fp code.  Is there a way to unambiguously resolve this issue, or
> at least resolve it to everyones satisfaction?
>
A patch for a related issue just appeared for gas-arm-Linux and
gas-arm-NetBSD...
<http://sources.redhat.com/ml/binutils/2003-06/msg00494.html>
<http://sources.redhat.com/ml/binutils/2003-06/msg00497.html>

Perhaps a similar route could be followed (I.E: -mfpu=none) to
support developers that need the "never, ever, for any reason"
touch the fp registers.
I imagine that option would just select a register/mode description
that does not mention fp registers. Ports might have to add 
descriptor support for this option.

Mike
>
> How would one do this? Visually inspect generated fp code? Run
> benchmarks? Which benchmarks?
>
> --linas