On Thu, Oct 23, 2014 at 06:52:20PM +0100, Charles Baylis wrote: > ( tl;dr: How do I handle intrinsic or builtin functions where there > are restrictions on the arguments which can't be represented in a C > function prototype? Do other ports have this problem, how do they > solve it? Language extension for C++98 to provide static_assert?)
In the builtin expand, you can get the operands' predicates from the insn_data array entry for the RTL pattern generated for that builtin. If the predicate is false, do a copy_to_mode_reg; if then the predicate is still false, assume it had to be some constant and error out. This works well; I stole the method from the tile* ports. It may need tweaks for your port. Segher