* gas/config/tc-arm.c (do_t_it): Fully initialise now_it.
(new_automatic_it_block): Likewise.
(handle_it_block): Record whether current instruction is
conditionally executed.
* gas/config/tc-arm.c (depr_insn_mask): New structure.
(depr_it_insns): New variable.
(it_fsm_post_encode): Warn on deprecated uses.
* gas/config/tc-arm.h (current_it): Add new fields.
* gas/testsuite/gas/arm/armv8-a-it-bad.d: New testcase.
* gas/testsuite/gas/arm/armv8-a-it-bad.l: Likewise.
* gas/testsuite/gas/arm/armv8-a-it-bad.s: Likewise.
* gas/testsuite/gas/arm/ldr-t-bad.s: Update testcase.
* gas/testsuite/gas/arm/ldr-t.d: Likewise.
* gas/testsuite/gas/arm/ldr-t.s: Likewise.
* gas/testsuite/gas/arm/neon-cond-bad-inc.s: Likewise.
* gas/testsuite/gas/arm/sp-pc-validations-bad-t: Likewise.
* gas/testsuite/gas/arm/vfp-fma-inc.s: Likewise.
* gas/testsuite/gas/arm/vfp-neon-syntax-inc.s: Likewise.