[AArch64] PR rtl-optimization/68796 Add compare-of-zero_extract pattern

[AArch64] PR rtl-optimization/68796 Add compare-of-zero_extract pattern

	PR rtl-optimization/68796
	* config/aarch64/aarch64.md (*and<mode>3nr_compare0_zextract):
	New pattern.
	* config/aarch64/aarch64.c (aarch64_select_cc_mode): Handle
	ZERO_EXTRACT comparison with zero.
	(aarch64_mask_from_zextract_ops): New function.
	* config/aarch64/aarch64-protos.h (aarch64_mask_from_zextract_ops):
	New prototype.

	* gcc.target/aarch64/tst_3.c: New test.
	* gcc.target/aarch64/tst_4.c: Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@231810 138bc75d-0d04-0410-961f-82ee72b054a4