[PATCH] Recognize sqrt(1.0/x) as rsqrt.d on MIPS4

Richard Sandiford rsandifo@redhat.com
Tue Aug 10 15:55:00 GMT 2004


Roger Sayle <roger@eyesopen.com> writes:
> One solution is for the GCC middle-end to choose one form or the other
> as the canonical RTL representation of reciprocal square root when the
> flag_unsafe_math_optimizations flag is set, and then always simplify
> RTL to that form.  This requires updating all affected targets to ensure
> that their patterns reflect the chosen canonical form.

But don't you think that's the right way to go?

I object to the patch you posted.  This seems no better than having
each backend match (minus ... (const_int X)) as an alternative to
(plus ... (const_int -X)), etc.

Richard



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