[Aarch64] Exploiting BFXIL when OR-ing two AND-operations with appropriate bitmasks

[Aarch64] Exploiting BFXIL when OR-ing two AND-operations with appropriate bitmasks

2018-09-13  Sam Tebbs  <sam.tebbs@arm.com>

	PR target/85628
	* config/aarch64/aarch64.md (*aarch64_bfxil):
	Define.
	* config/aarch64/constraints.md (Ulc): Define.
	* config/aarch64/aarch64-protos.h (aarch64_high_bits_all_ones_p):
	Define.
	* config/aarch64/aarch64.c (aarch64_high_bits_all_ones_p):
	New function.

	* gcc.target/aarch64/combine_bfxil.c: New file.
	* gcc.target/aarch64/combine_bfxil_2.c: New file.

From-SVN: r264264