Re: [PATCH] Optimize sin(atan(x)) and cos(atan(x)), take 3 (PR tree-optimization/86829)

[Jeff Law <law at redhat dot com>]

On 10/9/18 5:29 PM, Giuliano Augusto Faulin Belinassi wrote:
> Fixed all issues pointed in the previous iteration.
> There is now a significant change regarding how the sin(atan(x))
> constant is calculated, as now it checks for which values such that
> computing 1 + x*x won't overflow. There are two reasons for this
> change: (1) Avoid an intermediate infinity value when optimizing
> cos(atan(x)), and (2) avoid the requirement of separate constants for
> sin(atan(x)) and cos(atan(x)), thus making easier to maintain the
> code.
> 
> gcc/ChangeLog
> 
> 2018-10-09  Giuliano Belinassi  <giuliano.belinassi@usp.br>
> 
>     PR tree-optimization/86829
>     * match.pd: Added sin(atan(x)) and cos(atan(x)) simplification rules.
>     * real.c (build_sinatan_real): New function to build a constant equal to the
>     largest value c such that 1 + c*c will not overflow.
>     * real.h (build_sinatan_real): Allows this function to be called externally.
> 
> gcc/testsuite/gcc.dg/ChangeLog
> 
> 2018-10-09  Giuliano Belinassi  <giuliano.belinassi@usp.br>
> 
>     PR tree-optimization/86829
>     * gcc.dg/sinatan-1.c: New test.
>     * gcc.dg/sinatan-2.c: New test.
>     * gcc.dg/sinatan-3.c: New test.
> 
> There are no tests broken in trunk that seems related to this PR.
THanks.  I've installed this onto the trunk.  It's right at the
borderline of what would require a copyright assignment.  So if you're
going to do further work on GCC you should go ahead and start the
copyright assignment process.

Jeff