[Patch AArch64] Fix up BSL expander for floating point types

[Patch AArch64] Fix up BSL expander for floating point types

gcc/

	* config/aarch64/aarch64-simd.md
	(aarch64_simd_bsl<mode>_internal): Remove float cases, canonicalize.
	(aarch64_simd_bsl<mode>): Add gen_lowpart expressions where we
	are punning between float vectors and integer vectors.

gcc/testsuite/

	* gcc.target/aarch64/vbslq_f64_1.c: New.
	* gcc.target/aarch64/vbslq_f64_2.c: Likewise.
	* gcc.target/aarch64/vbslq_u64_1.c: Likewise.
	* gcc.target/aarch64/vbslq_u64_2.c: Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@217362 138bc75d-0d04-0410-961f-82ee72b054a4