synth: minor refactoring for clean-up.

3 files changed, 75 insertions, 90 deletions

diff --git a/src/synth/synth-environment.adb b/src/synth/synth-environment.adb
index 5270c3c0e..d6bb29883 100644
--- a/src/synth/synth-environment.adb
+++ b/src/synth/synth-environment.adb
@@ -1239,6 +1239,51 @@ package body Synth.Environment is
       end loop;
    end Extract_Merge_Partial_Assigns;
 
+   function Is_Assign_Value_Array_Static
+     (Wid : Wire_Id; Arr : Seq_Assign_Value_Array) return Memtyp
+   is
+      Res : Memtyp;
+      Prev_Val : Memtyp;
+   begin
+      Prev_Val := Null_Memtyp;
+      for I in Arr'Range loop
+         case Arr (I).Is_Static is
+            when False =>
+               --  A value is not static.
+               return Null_Memtyp;
+            when Unknown =>
+               if Prev_Val = Null_Memtyp then
+                  --  First use of previous value.
+                  if not Is_Static_Wire (Wid) then
+                     --  The previous value is not static.
+                     return Null_Memtyp;
+                  end if;
+                  Prev_Val := Get_Static_Wire (Wid);
+                  if Res /= Null_Memtyp then
+                     --  There is already a result.
+                     if not Is_Equal (Res, Prev_Val) then
+                        --  The previous value is different from the result.
+                        return Null_Memtyp;
+                     else
+                        Res := Prev_Val;
+                     end if;
+                  end if;
+               end if;
+            when True =>
+               if Res = Null_Memtyp then
+                  --  First value.  Keep it.
+                  Res := Arr (I).Val;
+               else
+                  if not Is_Equal (Res, Arr (I).Val) then
+                     --  Value is different.
+                     return  Null_Memtyp;
+                  end if;
+               end if;
+         end case;
+      end loop;
+      return Res;
+   end Is_Assign_Value_Array_Static;
+
    procedure Partial_Assign_Init (List : out Partial_Assign_List) is
    begin
       List := (First | Last => No_Partial_Assign);
@@ -1365,30 +1410,6 @@ package body Synth.Environment is
       Merge_Partial_Assigns (Ctxt, W, List);
    end Merge_Assigns;
 
-   --  Force the value of a Seq_Assign to be a net if needed, return it.
-   function Get_Assign_Value_Force (Val : Seq_Assign_Value)
-                                   return Partial_Assign
-   is
-      N : Net;
-   begin
-      case Val.Is_Static is
-         when Unknown =>
-            return No_Partial_Assign;
-         when True =>
-            N := Synth.Context.Get_Memtyp_Net (Val.Val);
-            return New_Partial_Assign (N, 0);
-         when False =>
-            return Val.Asgns;
-      end case;
-   end Get_Assign_Value_Force;
-
-   --  Force the value of a Seq_Assign to be a net if needed, return it.
-   function Get_Assign_Partial_Force (Asgn : Seq_Assign)
-                                     return Partial_Assign is
-   begin
-      return Get_Assign_Value_Force (Get_Seq_Assign_Value (Asgn));
-   end Get_Assign_Partial_Force;
-
    function Merge_Static_Assigns (Wid : Wire_Id; Tv, Fv : Seq_Assign_Value)
                                  return Boolean
    is
diff --git a/src/synth/synth-environment.ads b/src/synth/synth-environment.ads
index 74d0c3350..5d066bf43 100644
--- a/src/synth/synth-environment.ads
+++ b/src/synth/synth-environment.ads
@@ -167,30 +167,12 @@ package Synth.Environment is
    type Partial_Assign is private;
    No_Partial_Assign : constant Partial_Assign;
 
-   type Seq_Assign_Value (Is_Static : Tri_State_Type := True) is record
-      case Is_Static is
-         when Unknown =>
-            --  Used only for no value (in that case, it will use the previous
-            --  value).
-            --  This is used only for temporary handling, and is never stored
-            --  in Seq_Assign.
-            null;
-         when True =>
-            Val : Memtyp;
-         when False =>
-            --  Values assigned.
-            Asgns : Partial_Assign;
-      end case;
-   end record;
-
+   type Seq_Assign_Value is private;
    No_Seq_Assign_Value : constant Seq_Assign_Value;
 
    function Get_Assign_Partial (Asgn : Seq_Assign) return Partial_Assign;
    function Get_Seq_Assign_Value (Asgn : Seq_Assign) return Seq_Assign_Value;
 
-   --  Force the value of a Seq_Assign to be a net if needed, return it.
-   function Get_Assign_Partial_Force (Asgn : Seq_Assign) return Partial_Assign;
-
    function New_Partial_Assign (Val : Net; Offset : Uns32)
                                return Partial_Assign;
 
@@ -198,6 +180,17 @@ package Synth.Environment is
 
    type Seq_Assign_Value_Array is array (Int32 range <>) of Seq_Assign_Value;
 
+   --  Return the unique value from array of Seq_Assign_Value if it exists,
+   --  otherwise return Null_Memtyp.
+   --  To be more precise, a value is returned iff:
+   --   1) All present values in Arr are static
+   --   2) There is no missing values *or* the previous value is static.
+   --   3) All the values are equal.
+   --  then assign directly.
+   --  WID is used in case of unknown value.
+   function Is_Assign_Value_Array_Static
+     (Wid : Wire_Id; Arr : Seq_Assign_Value_Array) return Memtyp;
+
    type Partial_Assign_List is limited private;
 
    procedure Partial_Assign_Init (List : out Partial_Assign_List);
@@ -294,6 +287,22 @@ private
       Nbr_Final_Assign : Natural;
    end record;
 
+   type Seq_Assign_Value (Is_Static : Tri_State_Type := True) is record
+      case Is_Static is
+         when Unknown =>
+            --  Used only for no value (in that case, it will use the previous
+            --  value).
+            --  This is used only for temporary handling, and is never stored
+            --  in Seq_Assign.
+            null;
+         when True =>
+            Val : Memtyp;
+         when False =>
+            --  Values assigned.
+            Asgns : Partial_Assign;
+      end case;
+   end record;
+
    No_Seq_Assign_Value : constant Seq_Assign_Value := (Is_Static => Unknown);
 
    type Seq_Assign_Record is record
diff --git a/src/synth/synth-stmts.adb b/src/synth/synth-stmts.adb
index 88fa1df4c..0ebdf073f 100644
--- a/src/synth/synth-stmts.adb
+++ b/src/synth/synth-stmts.adb
@@ -1066,54 +1066,9 @@ package body Synth.Stmts is
             --  3) The default value is unused *or* it is static
             --  4) All the values are equal.
             --  then assign directly.
-            Sval := Null_Memtyp;
-            declare
-               Prev_Val : Memtyp;
-            begin
-               Prev_Val := Null_Memtyp;
-               for I in Pasgns'Range loop
-                  case Pasgns (I).Is_Static is
-                     when False =>
-                        Sval := Null_Memtyp;
-                        --  It's over.
-                        exit;
-                     when Unknown =>
-                        if Prev_Val = Null_Memtyp then
-                           if not Is_Static_Wire (Wi) then
-                              Sval := Null_Memtyp;
-                              --  It's over.
-                              exit;
-                           end if;
-                           Prev_Val := Get_Static_Wire (Wi);
-                        end if;
-                        if Sval /= Null_Memtyp
-                          and then not Is_Equal (Sval, Prev_Val)
-                        then
-                           Sval := Null_Memtyp;
-                           --  It's over.
-                           exit;
-                        end if;
-                     when True =>
-                        if Sval = Null_Memtyp then
-                           Sval := Pasgns (I).Val;
-                           if Prev_Val /= Null_Memtyp
-                             and then not Is_Equal (Sval, Prev_Val)
-                           then
-                              Sval := Null_Memtyp;
-                              --  It's over.
-                              exit;
-                           end if;
-                        else
-                           if not Is_Equal (Sval, Pasgns (I).Val) then
-                              Sval := Null_Memtyp;
-                              --  It's over.
-                              exit;
-                           end if;
-                        end if;
-                  end case;
-               end loop;
-            end;
+            Sval := Is_Assign_Value_Array_Static (Wi, Pasgns.all);
             if Sval /= Null_Memtyp then
+               --  Use static assignment.
                Phi_Assign_Static (Wi, Sval);
             else
                --  Compute the final value for each partial part of the wire.