Use combined_fn in tree-ssa-reassoc.c
Another patch to extend uses of built_in_function to combined_fn, this time
in tree-ssa-reassoc.c.
Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.
gcc/
* tree-ssa-reassoc.c: Include case-cfn-macros.h.
(stmt_is_power_of_op): Use combined_fn instead of built-in codes.
(decrement_power, acceptable_pow_call): Likewise.
(attempt_builtin_copysign): Likewise.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@230480 138bc75d-0d04-0410-961f-82ee72b054a4