diff options
Diffstat (limited to 'gcc/ada/sinfo.ads')
| -rw-r--r-- | gcc/ada/sinfo.ads | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/gcc/ada/sinfo.ads b/gcc/ada/sinfo.ads index ffb44d11a43..5a20bc7cf49 100644 --- a/gcc/ada/sinfo.ads +++ b/gcc/ada/sinfo.ads @@ -621,10 +621,15 @@ package Sinfo is -- A flag present in the N_Assignment_Statement node. It is used only -- if the type being assigned is an array type, and is set if analysis -- determines that it is definitely safe to do the copy backwards, i.e. - -- starting at the highest addressed element. Note that if neither of the - -- flags Forwards_OK or Backwards_OK is set, it means that the front end - -- could not determine that either direction is definitely safe, and a - -- runtime check may be required if the backend cannot figure it out. + -- starting at the highest addressed element. This is the case if either + -- the operands do not overlap, or they may overlap, but if they do, + -- then the left operand is at a higher address than the right operand. + -- + -- Note: If neither of the flags Forwards_OK or Backwards_OK is set, it + -- means that the front end could not determine that either direction is + -- definitely safe, and a runtime check may be required if the backend + -- cannot figure it out. If both flags Forwards_OK and Backwards_OK are + -- set, it means that the front end can assure no overlap of operands. -- Body_To_Inline (Node3-Sem) -- present in subprogram declarations. Denotes analyzed but unexpanded @@ -1023,10 +1028,15 @@ package Sinfo is -- A flag present in the N_Assignment_Statement node. It is used only -- if the type being assigned is an array type, and is set if analysis -- determines that it is definitely safe to do the copy forwards, i.e. - -- starting at the lowest addressed element. Note that if neither of the - -- flags Forwards_OK or Backwards_OK is set, it means that the front end - -- could not determine that either direction is definitely safe, and a - -- runtime check is required. + -- starting at the lowest addressed element. This is the case if either + -- the operands do not overlap, or they may overlap, but if they do, + -- then the left operand is at a lower address than the right operand. + -- + -- Note: If neither of the flags Forwards_OK or Backwards_OK is set, it + -- means that the front end could not determine that either direction is + -- definitely safe, and a runtime check may be required if the backend + -- cannot figure it out. If both flags Forwards_OK and Backwards_OK are + -- set, it means that the front end can assure no overlap of operands. -- From_At_End (Flag4-Sem) -- This flag is set on an N_Raise_Statement node if it corresponds to |