This clears some confusion between them by citing the definition of the
eponymous attributes in the RM and writing down their relationship.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* einfo.ads (Aft_Value): Adjust documentation.
(Scale_Value): Likewise.diff --git a/gcc/ada/einfo.ads b/gcc/ada/einfo.ads
--- a/gcc/ada/einfo.ads
+++ b/gcc/ada/einfo.ads
@@ -420,8 +420,10 @@ package Einfo is
-- output of certain warnings.
-- Aft_Value (synthesized)
--- Applies to fixed and decimal types. Computes a universal integer that
--- holds value of the Aft attribute for the type.
+-- Applies to fixed-point types and subtypes. This yields the value of
+-- the Aft attribute for the type, i.e. the number of decimal digits
+-- needed after the decimal point to accommodate the delta of the type,
+-- unless the delta is greater than 0.1, in which case it is 1.
-- Alias (Node18)
-- Defined in overloadable entities (literals, subprograms, entries) and
@@ -4263,9 +4265,10 @@ package Einfo is
-- explicit range).
-- Scale_Value (Uint16)
--- Defined in decimal fixed-point types and subtypes. Contains the scale
--- for the type (i.e. the value of type'Scale = the number of decimal
--- digits after the decimal point).
+-- Defined in decimal fixed-point types and subtypes. This holds the
+-- value of the Scale attribute for the type, i.e. the scale of the type
+-- defined as the integer N such that the delta is equal to 10.0**(-N).
+-- Note that, if Scale_Value is positive, then it is equal to Aft_Value.
-- Scope (Node3)
-- Defined in all entities. Points to the entity for the scope (block,
