ada: cleanup documentation for shift and rotate

Documentation updated.

gcc/ada/ChangeLog:

	* sinfo.ads (Shift_Count_OK): Update comments.
	(Is_Power_Of_2_For_Shift): Likewise.

1 files changed, 16 insertions, 18 deletions

diff --git a/gcc/ada/sinfo.ads b/gcc/ada/sinfo.ads
index 3db084e..2b82ab3 100644
--- a/gcc/ada/sinfo.ads
+++ b/gcc/ada/sinfo.ads
@@ -1812,16 +1812,15 @@ package Sinfo is
    --    A flag set on an aggregate that uses parentheses as delimiters
 
    --  Is_Power_Of_2_For_Shift
-   --    A flag present only in N_Op_Expon nodes. It is set when the
-   --    exponentiation is of the form 2 ** N, where the type of N is an
-   --    unsigned integral subtype whose size does not exceed the size of
-   --    Standard_Integer (i.e. a type that can be safely converted to
-   --    Natural), and the exponentiation appears as the right operand of an
-   --    integer multiplication or an integer division where the dividend is
-   --    unsigned. It is also required that overflow checking is off for both
-   --    the exponentiation and the multiply/divide node. If this set of
-   --    conditions holds, and the flag is set, then the division or
-   --    multiplication can be (and is) converted to a shift.
+   --    Present in N_Op_Expon nodes. It is set when the exponentiation is of
+   --    the form 2 ** N, where the type of N is an integer subtype whose size
+   --    does not exceed the size of Standard.Integer (i.e. a type that can be
+   --    safely converted to Natural), and the exponentiation appears as the
+   --    right operand of an integer multiplication or an integer division
+   --    where the dividend is unsigned. It is also required that overflow
+   --    checking is off for both the exponentiation and the multiply/divide
+   --    node. If this set of conditions holds, and the flag is set, then the
+   --    division or multiplication is converted to a shift.
 
    --  Is_Preelaborable_Call
    --    Present in call marker nodes. Set when the related call is non-static
@@ -2291,7 +2290,8 @@ package Sinfo is
    --    known to be in range, i.e. is in the range from zero to word length
    --    minus one. If this flag is not set, then the shift count may be
    --    outside this range, i.e. larger than the word length, and the code
-   --    must ensure that such shift counts give the appropriate result.
+   --    generated by the back end must ensure that such shift counts give the
+   --    appropriate result.
 
    --  Source_Type
    --    Used in an N_Validate_Unchecked_Conversion node to point to the
@@ -7738,15 +7738,13 @@ package Sinfo is
       --  operator names. Note that for a given shift operation, one node
       --  covers all possible types, as for normal operators.
 
-      --  Note: it is perfectly permissible for the expander to generate
-      --  shift operation nodes directly, in which case they will be analyzed
-      --  and parsed in the usual manner.
-
       --  Sprint syntax: shift-function-name!(expr, count)
 
-      --  Note: the Left_Opnd field holds the first argument (the value to
-      --  be shifted). The Right_Opnd field holds the second argument (the
-      --  shift count). The Chars field is the name of the intrinsic function.
+      --  The Left_Opnd field holds the first argument (the value to be
+      --  shifted). The Right_Opnd field holds the second argument (the shift
+      --  count). The Chars field is the name of the intrinsic function.
+      --  The back end is responsible for generating correct code in the case
+      --  of large shift counts (in which case Shift_Count_OK will be False).
 
       --  N_Op_Rotate_Left
       --  Sloc points to the function name