[ARM, AArch64] Make aarch-common.c files more robust.

[ARM, AArch64] Make aarch-common.c files more robust.

gcc/
	* config/arm/aarch-common.c
	(search_term): New typedef.
	(shift_rtx_costs): New array.
	(arm_rtx_shift_left_p): New.
	(arm_find_sub_rtx_with_search_term): Likewise.
	(arm_find_sub_rtx_with_code): Likewise.
	(arm_early_load_addr_dep): Add sanity checking.
	(arm_no_early_alu_shift_dep): Likewise.
	(arm_no_early_alu_shift_value_dep): Likewise.
	(arm_no_early_mul_dep): Likewise.
	(arm_no_early_store_addr_dep): Likewise.

From-SVN: r204575