[Bug middle-end/66588] combine should try transforming if_then_else of zero_extends into zero_extend of if_then_else

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66588

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Uroš Bizjak from comment #1)
> BTW: x86_64 is missing any form of zero-extended cmove.

... please see [1] how x86_64 implements it (*movsicc_noc_zext).

[1] https://gcc.gnu.org/ml/gcc-patches/2015-06/msg01306.html