Reorder the statement to subtract the old derivative value in assig op

closes vgvassilev#650
vaithak · Jan 25, 2024 · fa59708 · fa59708
1 parent 93cc725
commit fa59708
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Showing 9 changed files with 77 additions and 67 deletions.
diff --git a/lib/Differentiator/ReverseModeVisitor.cpp b/lib/Differentiator/ReverseModeVisitor.cpp
@@ -2393,8 +2393,10 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
       if (!isPointerOp)
         oldValue = StoreAndRef(AssignedDiff, direction::reverse, "_r_d",
                                /*forceDeclCreation=*/true);
-
       if (opCode == BO_Assign) {
+        // Add the statement `dl -= oldValue;`
+        addToCurrentBlock(BuildOp(BO_SubAssign, AssignedDiff, oldValue),
+                          direction::reverse);
         Rdiff = Visit(R, oldValue);
         valueForRevPass = Rdiff.getRevSweepAsExpr();
       } else if (opCode == BO_AddAssign) {
@@ -2423,6 +2425,9 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
         //   double r = _ref0 *= z;
         if (isInsideLoop)
           addToCurrentBlock(LCloned, direction::forward);
+        // Add the statement `dl -= oldValue;`
+        addToCurrentBlock(BuildOp(BO_SubAssign, AssignedDiff, oldValue),
+                          direction::reverse);
         /// Capture all the emitted statements while visiting R
         /// and insert them after `dl += dl * R`
         beginBlock(direction::reverse);
@@ -2439,6 +2444,9 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
                                   Ldiff.getRevSweepAsExpr());
         std::tie(Ldiff, Rdiff) = std::make_pair(LCloned, Rdiff.getExpr());
       } else if (opCode == BO_DivAssign) {
+        // Add the statement `dl -= oldValue;`
+        addToCurrentBlock(BuildOp(BO_SubAssign, AssignedDiff, oldValue),
+                          direction::reverse);
         auto RDelayed = DelayedGlobalStoreAndRef(R);
         StmtDiff RResult = RDelayed.Result;
         Expr* RStored =
@@ -2464,10 +2472,6 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
       if (m_ExternalSource)
         m_ExternalSource->ActBeforeFinalisingAssignOp(LCloned, oldValue);
 
-      // Update the derivative.
-      if (opCode != BO_SubAssign && opCode != BO_AddAssign)
-        addToCurrentBlock(BuildOp(BO_SubAssign, AssignedDiff, oldValue),
-                          direction::reverse);
       // Output statements from Visit(L).
       for (auto it = Lblock_begin; it != Lblock_end; ++it)
         addToCurrentBlock(*it, direction::reverse);