ForwardMode: extractvalue inst (rust-lang#354)

Author: tgymnich

enzyme/Enzyme/AdjointGenerator.h

@@ -1260,33 +1260,56 @@ class AdjointGenerator
     if (EVI.getType()->isPointerTy())
       return;
 
-    if (Mode == DerivativeMode::ReverseModePrimal)
+    switch (Mode) {
+    case DerivativeMode::ForwardMode: {
+      IRBuilder<> Builder2(&EVI);
+      getForwardBuilder(Builder2);
+
+      Value *orig_aggregate = EVI.getAggregateOperand();
+
+      Value *diffe_aggregate =
+          gutils->isConstantValue(orig_aggregate)
+              ? ConstantAggregate::getNullValue(orig_aggregate->getType())
+              : diffe(orig_aggregate, Builder2);
+      Value *diffe =
+          Builder2.CreateExtractValue(diffe_aggregate, EVI.getIndices());
+
+      setDiffe(&EVI, diffe, Builder2);
       return;
+    }
+    case DerivativeMode::ReverseModeGradient:
+    case DerivativeMode::ReverseModeCombined: {
+      IRBuilder<> Builder2(EVI.getParent());
+      getReverseBuilder(Builder2);
 
-    Value *orig_op0 = EVI.getOperand(0);
+      Value *orig_op0 = EVI.getOperand(0);
 
-    IRBuilder<> Builder2(EVI.getParent());
-    getReverseBuilder(Builder2);
+      auto prediff = diffe(&EVI, Builder2);
 
-    auto prediff = diffe(&EVI, Builder2);
+      // todo const
+      if (!gutils->isConstantValue(orig_op0)) {
+        SmallVector<Value *, 4> sv;
+        for (auto i : EVI.getIndices())
+          sv.push_back(ConstantInt::get(Type::getInt32Ty(EVI.getContext()), i));
+        size_t size = 1;
+        if (EVI.getType()->isSized())
+          size =
+              (gutils->newFunc->getParent()->getDataLayout().getTypeSizeInBits(
+                   EVI.getType()) +
+               7) /
+              8;
+        ((DiffeGradientUtils *)gutils)
+            ->addToDiffe(orig_op0, prediff, Builder2, TR.addingType(size, &EVI),
+                         sv);
+      }
 
-    // todo const
-    if (!gutils->isConstantValue(orig_op0)) {
-      SmallVector<Value *, 4> sv;
-      for (auto i : EVI.getIndices())
-        sv.push_back(ConstantInt::get(Type::getInt32Ty(EVI.getContext()), i));
-      size_t size = 1;
-      if (EVI.getType()->isSized())
-        size = (gutils->newFunc->getParent()->getDataLayout().getTypeSizeInBits(
-                    EVI.getType()) +
-                7) /
-               8;
-      ((DiffeGradientUtils *)gutils)
-          ->addToDiffe(orig_op0, prediff, Builder2, TR.addingType(size, &EVI),
-                       sv);
+      setDiffe(&EVI, Constant::getNullValue(EVI.getType()), Builder2);
+      return;
+    }
+    case DerivativeMode::ReverseModePrimal: {
+      return;
+    }
     }
-
-    setDiffe(&EVI, Constant::getNullValue(EVI.getType()), Builder2);
   }
 
   void visitInsertValueInst(llvm::InsertValueInst &IVI) {