Merged commit includes the following changes:

179858783  by gunan:

    [XLA] Add a pass to replace all non-side-effecting and removable zero sized
    HLOs.

--
179853916  by A. Unique TensorFlower:

    Fix missing backtick in parse_example docstring, causing wrong markdown formatting.

--
179852823  by apassos:

    Another attempt at adding int64 indices to Fill.

--
179852553  by A. Unique TensorFlower:

    Stop grappler optimization to reorder BiasAdd ops.

--
179850703  by yaozhang:

    Support reverse op.

--
179850204  by blakehechtman:

    [XLA] Add a pass to replace all non-side-effecting and removable zero sized
    HLOs.

--

PiperOrigin-RevId: 179858783

tensorflow/core/grappler/op_types.cc

@@ -225,6 +225,8 @@ bool IsRestore(const NodeDef& node) {
           node.op() == "RestoreSlice");
 }
 
+bool IsReverseV2(const NodeDef& node) { return node.op() == "ReverseV2"; }
+
 bool IsRsqrtGrad(const NodeDef& node) { return node.op() == "RsqrtGrad"; }
 
 bool IsSelect(const NodeDef& node) { return node.op() == "Select"; }

tensorflow/core/grappler/op_types.h

@@ -89,6 +89,7 @@ bool IsRecv(const NodeDef& node);
 bool IsReduction(const NodeDef& node);
 bool IsReshape(const NodeDef& node);
 bool IsRestore(const NodeDef& node);
+bool IsReverseV2(const NodeDef& node);
 bool IsRsqrtGrad(const NodeDef& node);
 bool IsSelect(const NodeDef& node);
 bool IsSeluGrad(const NodeDef& node);

tensorflow/core/grappler/optimizers/constant_folding.cc

@@ -1486,7 +1486,7 @@ Status ConstantFolding::SimplifyGraph(GraphDef* output,
     // TODO(rmlarsen): Handle non-associative/non-commutative operators like
     // subtraction and division, as well as mixed subtraction/addition,
     // division/multiplication.
-    if ((is_add || is_mul) && NumNonControlInputs(*node) == 2) {
+    if ((IsAdd(*node) || is_mul) && NumNonControlInputs(*node) == 2) {
       NodeDef* left_child = node_map_->GetNode(node->input(0));
       NodeDef* right_child = node_map_->GetNode(node->input(1));
       // One child must be constant, and the other the same op as the parent.