[flang] More documentation
Original-commit: flang-compiler/f18@7fd40e8598302c42d67f9ac63161e1c9f548ef46
Reviewed-on: https://github.com/flang-compiler/f18/pull/195
diff --git a/flang/documentation/intrinsics.md b/flang/documentation/intrinsics.md
index 43c7e37..c04020a 100644
--- a/flang/documentation/intrinsics.md
+++ b/flang/documentation/intrinsics.md
@@ -64,8 +64,10 @@
An `INTRINSIC` statement or attribute may have to be applied to an
unrestricted specific name to enable such usage.
-In such usage, the instance of the function that accepts and returns
-values of the default kinds of the intrinsic types is used.
+When a name is being used as a specific procedure for any purpose other
+than that of a called function, the specific instance of the function
+that accepts and returns values of the default kinds of the intrinsic
+types is used.
A Fortran `INTERFACE` could be written to define each of
these unrestricted specific intrinsic function names.
@@ -73,7 +75,14 @@
specific names must pass only scalar actual argument values.
No other intrinsic function name can be passed as an actual argument,
-used as a pointer target, or appear in a generic interface.
+used as a pointer target, appear in a generic interface, or be otherwise
+used except as the name of a called function.
+Some of these _restricted specific intrinsic functions_, e.g. `FLOAT`,
+provide a means for invoking a corresponding generic (`REAL` in the case of `FLOAT`)
+with forced argument and result kinds.
+Others, viz. `CHAR`, `ICHAR`, `INT`, `REAL`, and the lexical comparisons like `LGE`,
+have the same name as their generic functions, and it is not clear what purpose
+is accomplished by the standard by defining them as specific functions.
### Trigonometric elemental intrinsic functions, generic and (mostly) specific
All of these functions can be used as unrestricted specific names.
