aarch64: Fix up aarch64_simd_clone_compute_vecsize_and_simdlen [PR99542]

aarch64: Fix up aarch64_simd_clone_compute_vecsize_and_simdlen [PR99542]

As the patch shows, there are several bugs in
aarch64_simd_clone_compute_vecsize_and_simdlen.
One is that unlike for function declarations that aren't definitions
it completely ignores argument types.  Such decls don't have DECL_ARGUMENTS,
but we can walk TYPE_ARG_TYPES instead, like the i386 backend does or like
the simd cloning code in the middle end does too.

Another problem is that it checks types of uniform arguments.  That is
unnecessary, uniform arguments are passed the way it normally is, it is
a scalar argument rather than vector, so there is no reason not to support
uniform argument of different size, or long double, structure etc.

2021-03-16  Jakub Jelinek  <jakub@redhat.com>

	PR target/99542
	* config/aarch64/aarch64.c
	(aarch64_simd_clone_compute_vecsize_and_simdlen): If not a function
	definition, walk TYPE_ARG_TYPES list if non-NULL for argument types
	instead of DECL_ARGUMENTS.  Ignore types for uniform arguments.

	* gcc.dg/gomp/pr99542.c: New test.
	* gcc.dg/gomp/pr59669-2.c (bar): Don't expect a warning on aarch64.
	* gcc.dg/gomp/simd-clones-2.c (setArray): Likewise.
	* g++.dg/vect/simd-clone-7.cc (bar): Likewise.
	* g++.dg/gomp/declare-simd-1.C (f37): Expect a different warning
	on aarch64.
	* gcc.dg/declare-simd.c (fn2): Expect a new warning on aarch64.