[Ada] Removal of various ??? comments plus related code changes
gcc/ada/
* checks.adb: Remove calls of Set_Do_Tag_Check (N, False).
* einfo.ads: Remove hanging unneeded ??? comment ("this real description
was clobbered").
* exp_util.ads (Insert_Actions_After): Remove ??? from spec comment.
* gen_il-fields.ads (Opt_Field_Enum): Remove literals
Do_Accessibility_Check and Do_Tag_Check.
* gen_il-gen-gen_nodes.adb: Remove all calls to Sm for
Do_Accessibility_Check and Do_Tag_Check.
* sem_type.ads (Is_Subtype_Of): Remove obsolete ???
comment (function is not limited to scalar subtypes).
* sem_util.ads (Is_Local_Variable_Reference): Revise comment to
mention out-mode parameters as well, and remove ???.
(Propagate_Concurrent_Flags): Minor reformatting.
(Propagate_Invariant_Attributes): Typo fix.
(Propagate_Predicate_Attributes): Indicate what is propagated
and remove ??? comment.
* sem_util.adb (Cannot_Raise_Constraint_Error): Remove unneeded
test of Do_Tag_Check.
(Is_Local_Variable_Reference): Extend function to testing for
formals of mode out as well.
* sinfo.ads: Remove ??? comment about flag
Convert_To_Return_False indicating that the flag is obsolete (in
fact it's used). Remove references to Do_Accessibility_Check and
Do_Tag_Check (and the two associated ??? comments), as these
flags are unneeded.
* sinfo-cn.adb (Change_Conversion_To_Unchecked): Remove call of
Set_Do_Tag_Check (N, False).
* targparm.ads (Support_Atomic_Primitives_On_Target): Remove ???
comment, plus minor reformatting.