On Tue, May 07, 2019 at 09:48:13AM +0200, Richard Biener wrote:
> Will leave the "correctness check" for other folks but the above is
> better written as
>
> + (outer_op (inner_op @0 REAL_CST@1) REAL_CST@2)
> + (if (real_zerop (@1)
> + && real_zerop (@2)
>
> because that gets code-generated better. Btw, for -fsignalling-nans
Ok, will change. I want to introduce uniform_real_cst_p similar to
uniform_integer_cst_p incrementally and then it will change again.
> can we have a literal sNaN? Then you need :c on the inner_op since
> I'm not sure we canonicalize to sNaN + 0.0 rather than 0.0 + sNaN.
I had :c on both initially, but that doesn't compile, because MINUS_EXPR
is not commutative. And I wanted to avoid writing 4 patterns instead of 1.
> Maybe not worth optimizing though (since we rule out -frounding-math
> a similar case there doesn't need to be considered).
>
> > + && HONOR_SIGNED_ZEROS (element_mode (type))
> > + && !HONOR_SIGN_DEPENDENT_ROUNDING (element_mode (type)))
>
> You can write HONOR_SIGNED_ZEROS (type) here for brevity.
Ok, will do (and change it then in fold_real_zero_addition_p as well).
Jakub
