[Bug tree-optimization/89475] Teach ccp about __builtin_bswap{16,32,64}

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89475

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 45805
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45805&action=edit
gcc9-pr89475.patch

Untested improvement.  GCC10 material I guess.