aarch64.c (aarch64_invalid_conversion): New function for target hook.

gcc/ChangeLog:

2020-01-10  Stam Markianos-Wright  <stam.markianos-wright@arm.com>

	* config/aarch64/aarch64.c (aarch64_invalid_conversion): New function
	for target hook.
	(aarch64_invalid_unary_op): New function for target hook.
	(aarch64_invalid_binary_op): New function for target hook.

gcc/testsuite/ChangeLog:

2020-01-10  Stam Markianos-Wright  <stam.markianos-wright@arm.com>

	* g++.target/aarch64/bfloat_cpp_typecheck.C: New test.
	* gcc.target/aarch64/bfloat16_scalar_typecheck.c: New test.
	* gcc.target/aarch64/bfloat16_vector_typecheck_1.c: New test.
	* gcc.target/aarch64/bfloat16_vector_typecheck_2.c: New test.

From-SVN: r280130