Improve test coverage for pointer support

vgvassilev · Dec 20, 2023 · d44ce32 · d44ce32
1 parent eaa534a
commit d44ce32
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Showing 3 changed files with 50 additions and 43 deletions.
diff --git a/include/clad/Differentiator/VisitorBase.h b/include/clad/Differentiator/VisitorBase.h
@@ -578,6 +578,36 @@ namespace clad {
     /// store a pointer to their size expression.
     clang::QualType CloneType(clang::QualType T);
 
+    /// Computes effective derivative operands. It should be used when operands
+    /// might be of pointer types.
+    ///
+    /// In the trivial case, both operands are of non-pointer types, and the
+    /// effective derivative operands are `LDiff.getExpr_dx()` and
+    /// `RDiff.getExpr_dx()` respectively.
+    ///
+    /// Integers used in pointer arithmetic should be considered
+    /// non-differentiable entities. For example:
+    ///
+    /// ```
+    /// p + i;
+    /// ```
+    ///
+    /// Derived statement should be:
+    ///
+    /// ```
+    /// _d_p + i;
+    /// ```
+    ///
+    /// instead of:
+    ///
+    /// ```
+    /// _d_p + _d_i;
+    /// ```
+    ///
+    /// Therefore, effective derived expression of `i` is `i` instead of `_d_i`.
+    ///
+    /// This functions sets `derivedL` and `derivedR` arguments to effective
+    /// derived expressions.
     static void ComputeEffectiveDOperands(StmtDiff& LDiff, StmtDiff& RDiff,
                                           clang::Expr*& derivedL,
                                           clang::Expr*& derivedR);

diff --git a/lib/Differentiator/ReverseModeVisitor.cpp b/lib/Differentiator/ReverseModeVisitor.cpp
@@ -2060,6 +2060,8 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
         auto op = opCode == UO_PostInc ? UO_PostDec : UO_PostInc;
         addToCurrentBlock(BuildOp(op, Clone(diff.getRevSweepAsExpr())),
                           direction::reverse);
+        if (isPointerOp)
+          addToCurrentBlock(BuildOp(op, diff.getExpr_dx()), direction::reverse);
       }
 
       ResultRef = diff.getExpr_dx();
@@ -2121,15 +2123,18 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
         }
       }
       return {cloneE, derivedE};
-    } else if (opCode != UO_LNot) {
-      // We should not output any warning on visiting boolean conditions
-      // FIXME: We should support boolean differentiation or ignore it
-      // completely
-      unsupportedOpWarn(UnOp->getEndLoc());
-    } else if (isa<DeclRefExpr>(E))
-      diff = Visit(E);
-    else
-      diff = StmtDiff(E);
+    } else {
+      if (opCode != UO_LNot)
+        // We should not output any warning on visiting boolean conditions
+        // FIXME: We should support boolean differentiation or ignore it
+        // completely
+        unsupportedOpWarn(UnOp->getEndLoc());
+
+      if (isa<DeclRefExpr>(E))
+        diff = Visit(E);
+      else
+        diff = StmtDiff(E);
+    }
     Expr* op = BuildOp(opCode, diff.getExpr());
     return StmtDiff(op, ResultRef, nullptr, valueForRevPass);
   }
@@ -2391,15 +2396,17 @@ Expr* getArraySizeExpr(const ArrayType* AT, ASTContext& context,
           addToCurrentBlock(BuildOp(BO_AddAssign, AssignedDiff, oldValue),
                             direction::reverse);
         Rdiff = Visit(R, oldValue);
-        valueForRevPass = BuildOp(BO_Add, Rdiff.getRevSweepAsExpr(),
-                                  Ldiff.getRevSweepAsExpr());
+        if (!isPointerOp)
+          valueForRevPass = BuildOp(BO_Add, Rdiff.getRevSweepAsExpr(),
+                                    Ldiff.getRevSweepAsExpr());
       } else if (opCode == BO_SubAssign) {
         if (!isPointerOp)
           addToCurrentBlock(BuildOp(BO_AddAssign, AssignedDiff, oldValue),
                             direction::reverse);
         Rdiff = Visit(R, BuildOp(UO_Minus, oldValue));
-        valueForRevPass = BuildOp(BO_Sub, Rdiff.getRevSweepAsExpr(),
-                                  Ldiff.getRevSweepAsExpr());
+        if (!isPointerOp)
+          valueForRevPass = BuildOp(BO_Sub, Rdiff.getRevSweepAsExpr(),
+                                    Ldiff.getRevSweepAsExpr());
       } else if (opCode == BO_MulAssign) {
         // Create a reference variable to keep the result of LHS, since it
         // must be used on 2 places: when storing to a global variable

diff --git a/lib/Differentiator/VisitorBase.cpp b/lib/Differentiator/VisitorBase.cpp
@@ -782,36 +782,6 @@ namespace clad {
     return TAL.get(0).getAsType();
   }
 
-  /// Computes effective derivative operands. It should be used when operands
-  /// might be of pointer types.
-  ///
-  /// In the trivial case, both operands are of non-pointer types, and the
-  /// effective derivative operands are `LDiff.getExpr_dx()` and
-  /// `RDiff.getExpr_dx()` respectively.
-  ///
-  /// Integers used in pointer arithmetic should be considered
-  /// non-differentiable entities. For example:
-  ///
-  /// ```
-  /// p + i;
-  /// ```
-  ///
-  /// Derived statement should be:
-  ///
-  /// ```
-  /// _d_p + i;
-  /// ```
-  ///
-  /// instead of:
-  ///
-  /// ```
-  /// _d_p + _d_i;
-  /// ```
-  ///
-  /// Therefore, effective derived expression of `i` is `i` instead of `_d_i`.
-  ///
-  /// This functions sets `derivedL` and `derivedR` arguments to effective
-  /// derived expressions.
   void VisitorBase::ComputeEffectiveDOperands(StmtDiff& LDiff, StmtDiff& RDiff,
                                               clang::Expr*& derivedL,
                                               clang::Expr*& derivedR) {