Remove redundant Max(x, 0) for x positive

Code review

mindspore/ccsrc/frontend/optimizer/irpass/value_based_eliminate.cc

@@ -21,19 +21,10 @@ namespace opt {
 namespace irpass {
 #define UPPER_FLT_LIMIT (FLT_MAX / 2.0)
 #define LOWER_FLT_LIMIT (-FLT_MAX / 2.0)
+// Define the checking mode
+enum ScalarCheckingMode : int { GREATER_EQUAL = 0, LESS };
 
-bool IsCNodePositive(const AnfNodePtr &node) {
-  if (IsPrimitiveCNode(node, prim::kPrimReduceSum) || IsPrimitiveCNode(node, prim::kPrimSqueeze)) {
-    return IsCNodePositive(node->cast<CNodePtr>()->input(1));
-  }
-  if (IsPrimitiveCNode(node, prim::kPrimSquare) || IsPrimitiveCNode(node, prim::kPrimSqrt)) {
-    return true;
-  }
-  return false;
-}
-
-// check if a value is bigger than UPPER_FLT_LIMIT
-bool IsNodeScalarMaxFLT(const AnfNodePtr &node) {
+bool IsNodeScalarTrueWith(const AnfNodePtr &node, const ScalarCheckingMode &checking_mode, const float &check_value) {
   auto value_node = node->cast<ValueNodePtr>();
   if (value_node == nullptr) {
     return false;
@@ -47,7 +38,10 @@ bool IsNodeScalarMaxFLT(const AnfNodePtr &node) {
   auto scalar = value->cast<ScalarPtr>();
   if (scalar != nullptr) {
     if (scalar->isa<FloatImm>()) {
-      return GetValue<float>(scalar) > UPPER_FLT_LIMIT;
+      if (checking_mode == GREATER_EQUAL) {
+        return GetValue<float>(scalar) >= check_value;
+      }
+      return GetValue<float>(scalar) < check_value;
     }
   }
   // Check for Tensor [] or Tensor [1]
@@ -62,48 +56,42 @@ bool IsNodeScalarMaxFLT(const AnfNodePtr &node) {
   TypeId tensor_type = tensor_ptr->Dtype()->type_id();
   if ((tensor_type == TypeId::kNumberTypeFloat32) || (tensor_type == TypeId::kNumberTypeFloat)) {
     float *data = reinterpret_cast<float *>(tensor_ptr->data_c());
-    return data[0] > UPPER_FLT_LIMIT;
+    if (checking_mode == GREATER_EQUAL) {
+      return data[0] >= check_value;
+    }
+    return data[0] < check_value;
   }
 
   return false;
 }
 
-// check if a value is smaller than LOWER_FLT_LIMIT
-bool IsNodeScalarMinFLT(const AnfNodePtr &node) {
-  auto value_node = node->cast<ValueNodePtr>();
-  if (value_node == nullptr) {
-    return false;
-  }
+// check if a value is greater or equal 0.0
+bool IsNodeScalarPositive(const AnfNodePtr &node) { return IsNodeScalarTrueWith(node, GREATER_EQUAL, 0.0); }
 
-  auto value = value_node->value();
-  if (value == nullptr) {
-    return false;
-  }
-
-  auto scalar = value->cast<ScalarPtr>();
-  if (scalar != nullptr) {
-    if (scalar->isa<FloatImm>()) {
-      return GetValue<float>(scalar) < LOWER_FLT_LIMIT;
-    }
-  }
-  // Check for Tensor [] or Tensor [1]
-  auto tensor_ptr = value->cast<tensor::TensorPtr>();
-  if (tensor_ptr == nullptr) {
-    return false;
+bool IsCNodePositive(const AnfNodePtr &node) {
+  if (IsPrimitiveCNode(node, prim::kPrimReduceSum) || IsPrimitiveCNode(node, prim::kPrimSqueeze)) {
+    return IsCNodePositive(node->cast<CNodePtr>()->input(1));
   }
-  if (tensor_ptr->DataSize() > 1) {
-    return false;
+  if (IsPrimitiveCNode(node, prim::kPrimSquare) || IsPrimitiveCNode(node, prim::kPrimSqrt)) {
+    return true;
   }
-
-  TypeId tensor_type = tensor_ptr->Dtype()->type_id();
-  if ((tensor_type == TypeId::kNumberTypeFloat32) || (tensor_type == TypeId::kNumberTypeFloat)) {
-    float *data = reinterpret_cast<float *>(tensor_ptr->data_c());
-    return data[0] < LOWER_FLT_LIMIT;
+  if (IsPrimitiveCNode(node, prim::kPrimMinimum) || IsPrimitiveCNode(node, prim::kPrimRealDiv)) {
+    auto first_node_positive =
+      IsCNodePositive(node->cast<CNodePtr>()->input(1)) || IsNodeScalarPositive(node->cast<CNodePtr>()->input(1));
+    auto second_node_positive =
+      IsCNodePositive(node->cast<CNodePtr>()->input(2)) || IsNodeScalarPositive(node->cast<CNodePtr>()->input(2));
+    return first_node_positive && second_node_positive;
   }
 
   return false;
 }
 
+// check if a value is greater or equal UPPER_FLT_LIMIT
+bool IsNodeScalarMaxFLT(const AnfNodePtr &node) { return IsNodeScalarTrueWith(node, GREATER_EQUAL, UPPER_FLT_LIMIT); }
+
+// check if a value is smaller than LOWER_FLT_LIMIT
+bool IsNodeScalarMinFLT(const AnfNodePtr &node) { return IsNodeScalarTrueWith(node, LESS, LOWER_FLT_LIMIT); }
+
 AnfNodePtr ValueBasedEliminate::operator()(const OptimizerPtr &, const AnfNodePtr &node) {
   PatternNode x, y, z;
   PConstant zero_(node, false, 0);
@@ -116,10 +104,15 @@ AnfNodePtr ValueBasedEliminate::operator()(const OptimizerPtr &, const AnfNodePt
   MATCH_REPLACE_IF(node, PPrimitive(prim::kPrimSelect, PPrimitive(prim::kPrimGreater, x, zero_scalar_), y, z), y,
                    IsCNodePositive(x.GetNode(node)));
 
+  // {prim::kPrimMaximum, X, LOWER_FLT_LIMIT}} -> X
   MATCH_REPLACE_IF(node, PPrimitive(prim::kPrimMaximum, x, y), x, IsNodeScalarMinFLT(y.GetNode(node)));
 
+  // {prim::kPrimMinimum, X, UPPER_FLT_LIMIT}} -> X
   MATCH_REPLACE_IF(node, PPrimitive(prim::kPrimMinimum, x, y), x, IsNodeScalarMaxFLT(y.GetNode(node)));
 
+  // {prim::kPrimMaximum, X, 0}} -> X when X is always greater or equal 0
+  MATCH_REPLACE_IF(node, PPrimitive(prim::kPrimMaximum, x, zero_), x, IsCNodePositive(x.GetNode(node)));
+
   return nullptr;
 }