[turbofan] Improve representation selection for Smi checking.

src/compiler/effect-control-linearizer.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/effect-control-linearizer.h"
 
 #include "src/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/linkage.h"
@@ skipping 618 matching lines @@
       break;
     case IrOpcode::kCheckNumber:
       state = LowerCheckNumber(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckString:
       state = LowerCheckString(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckIf:
       state = LowerCheckIf(node, frame_state, *effect, *control);
       break;
-    case IrOpcode::kCheckTaggedPointer:
-      state = LowerCheckTaggedPointer(node, frame_state, *effect, *control);
-      break;
-    case IrOpcode::kCheckTaggedSigned:
-      state = LowerCheckTaggedSigned(node, frame_state, *effect, *control);
+    case IrOpcode::kCheckHeapObject:
+      state = LowerCheckHeapObject(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedInt32Add:
       state = LowerCheckedInt32Add(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedInt32Sub:
       state = LowerCheckedInt32Sub(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedInt32Div:
       state = LowerCheckedInt32Div(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedInt32Mod:
       state = LowerCheckedInt32Mod(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedUint32Div:
       state = LowerCheckedUint32Div(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedUint32Mod:
       state = LowerCheckedUint32Mod(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedInt32Mul:
       state = LowerCheckedInt32Mul(node, frame_state, *effect, *control);
       break;
+    case IrOpcode::kCheckedInt32ToTaggedSigned:
+      state =
+          LowerCheckedInt32ToTaggedSigned(node, frame_state, *effect, *control);
+      break;
     case IrOpcode::kCheckedUint32ToInt32:
       state = LowerCheckedUint32ToInt32(node, frame_state, *effect, *control);
       break;
+    case IrOpcode::kCheckedUint32ToTaggedSigned:
+      state = LowerCheckedUint32ToTaggedSigned(node, frame_state, *effect,
+                                               *control);
+      break;
     case IrOpcode::kCheckedFloat64ToInt32:
       state = LowerCheckedFloat64ToInt32(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedTaggedSignedToInt32:
       state =
           LowerCheckedTaggedSignedToInt32(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedTaggedToInt32:
       state = LowerCheckedTaggedToInt32(node, frame_state, *effect, *control);
       break;
     case IrOpcode::kCheckedTaggedToFloat64:
       state = LowerCheckedTaggedToFloat64(node, frame_state, *effect, *control);
       break;
+    case IrOpcode::kCheckedTaggedToTaggedSigned:
+      state = LowerCheckedTaggedToTaggedSigned(node, frame_state, *effect,
+                                               *control);
+      break;
     case IrOpcode::kTruncateTaggedToWord32:
       state = LowerTruncateTaggedToWord32(node, *effect, *control);
       break;
     case IrOpcode::kCheckedTruncateTaggedToWord32:
       state = LowerCheckedTruncateTaggedToWord32(node, frame_state, *effect,
                                                  *control);
       break;
     case IrOpcode::kObjectIsCallable:
       state = LowerObjectIsCallable(node, *effect, *control);
       break;
@@ skipping 621 matching lines @@
   Node* value = node->InputAt(0);
 
   control = effect =
       graph()->NewNode(common()->DeoptimizeUnless(DeoptimizeReason::kNoReason),
                        value, frame_state, effect, control);
 
   return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
-EffectControlLinearizer::LowerCheckTaggedPointer(Node* node, Node* frame_state,
-                                                 Node* effect, Node* control) {
+EffectControlLinearizer::LowerCheckHeapObject(Node* node, Node* frame_state,
+                                              Node* effect, Node* control) {
   Node* value = node->InputAt(0);
 
   Node* check = ObjectIsSmi(value);
   control = effect =
       graph()->NewNode(common()->DeoptimizeIf(DeoptimizeReason::kSmi), check,
                        frame_state, effect, control);
 
   return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
-EffectControlLinearizer::LowerCheckTaggedSigned(Node* node, Node* frame_state,
-                                                Node* effect, Node* control) {
-  Node* value = node->InputAt(0);
-
-  Node* check = ObjectIsSmi(value);
-  control = effect =
-      graph()->NewNode(common()->DeoptimizeUnless(DeoptimizeReason::kNotASmi),
-                       check, frame_state, effect, control);
-
-  return ValueEffectControl(value, effect, control);
-}
-
-EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerCheckedInt32Add(Node* node, Node* frame_state,
                                               Node* effect, Node* control) {
   Node* lhs = node->InputAt(0);
   Node* rhs = node->InputAt(1);
 
   Node* value =
       graph()->NewNode(machine()->Int32AddWithOverflow(), lhs, rhs, control);
 
   Node* check = graph()->NewNode(common()->Projection(1), value, control);
   control = effect =
@@ skipping 305 matching lines @@
 
     control = graph()->NewNode(common()->Merge(2), if_zero, if_not_zero);
     effect = graph()->NewNode(common()->EffectPhi(2), e_if_zero, e_if_not_zero,
                               control);
   }
 
   return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
+EffectControlLinearizer::LowerCheckedInt32ToTaggedSigned(Node* node,
+                                                         Node* frame_state,
+                                                         Node* effect,
+                                                         Node* control) {
+  DCHECK(SmiValuesAre31Bits());
+  Node* value = node->InputAt(0);
+
+  Node* add = graph()->NewNode(machine()->Int32AddWithOverflow(), value, value,
+                               control);
+
+  Node* check = graph()->NewNode(common()->Projection(1), add, control);
+  control = effect =
+      graph()->NewNode(common()->DeoptimizeIf(DeoptimizeReason::kOverflow),
+                       check, frame_state, effect, control);
+
+  value = graph()->NewNode(common()->Projection(0), add, control);
+
+  return ValueEffectControl(value, effect, control);
+}
+
+EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerCheckedUint32ToInt32(Node* node,
                                                    Node* frame_state,
                                                    Node* effect,
                                                    Node* control) {
   Node* value = node->InputAt(0);
   Node* max_int = jsgraph()->Int32Constant(std::numeric_limits<int32_t>::max());
   Node* is_safe =
       graph()->NewNode(machine()->Uint32LessThanOrEqual(), value, max_int);
   control = effect = graph()->NewNode(
       common()->DeoptimizeUnless(DeoptimizeReason::kLostPrecision), is_safe,
       frame_state, effect, control);
 
   return ValueEffectControl(value, effect, control);
 }
 
 EffectControlLinearizer::ValueEffectControl
+EffectControlLinearizer::LowerCheckedUint32ToTaggedSigned(Node* node,
+                                                          Node* frame_state,
+                                                          Node* effect,
+                                                          Node* control) {
+  Node* value = node->InputAt(0);
+  Node* check = graph()->NewNode(machine()->Uint32LessThanOrEqual(), value,
+                                 SmiMaxValueConstant());
+  control = effect = graph()->NewNode(
+      common()->DeoptimizeUnless(DeoptimizeReason::kLostPrecision), check,

[Jarin, 2016/09/23 08:31:54]

So why is the deopt reason here kLostPrecision and above it is kOverflow?

[Benedikt Meurer, 2016/09/23 08:39:38]

Copied your logic from above.

+      frame_state, effect, control);
+  value = ChangeUint32ToSmi(value);
+
+  return ValueEffectControl(value, effect, control);
+}
+
+EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::BuildCheckedFloat64ToInt32(CheckForMinusZeroMode mode,
                                                     Node* value,
                                                     Node* frame_state,
                                                     Node* effect,
                                                     Node* control) {
   Node* value32 = graph()->NewNode(machine()->RoundFloat64ToInt32(), value);
   Node* check_same = graph()->NewNode(
       machine()->Float64Equal(), value,
       graph()->NewNode(machine()->ChangeInt32ToFloat64(), value32));
   control = effect = graph()->NewNode(
@@ skipping 184 matching lines @@
   Node* effect_phi = graph()->NewNode(common()->EffectPhi(2), etrue,
                                       number_state.effect, merge);
   Node* result =
       graph()->NewNode(common()->Phi(MachineRepresentation::kFloat64, 2), vtrue,
                        number_state.value, merge);
 
   return ValueEffectControl(result, effect_phi, merge);
 }
 
 EffectControlLinearizer::ValueEffectControl
+EffectControlLinearizer::LowerCheckedTaggedToTaggedSigned(Node* node,
+                                                          Node* frame_state,
+                                                          Node* effect,
+                                                          Node* control) {
+  Node* value = node->InputAt(0);
+
+  Node* check = ObjectIsSmi(value);
+  control = effect =
+      graph()->NewNode(common()->DeoptimizeUnless(DeoptimizeReason::kNotASmi),
+                       check, frame_state, effect, control);
+
+  return ValueEffectControl(value, effect, control);
+}
+
+EffectControlLinearizer::ValueEffectControl
 EffectControlLinearizer::LowerTruncateTaggedToWord32(Node* node, Node* effect,
                                                      Node* control) {
   Node* value = node->InputAt(0);
 
   Node* check = ObjectIsSmi(value);
   Node* branch =
       graph()->NewNode(common()->Branch(BranchHint::kTrue), check, control);
 
   Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
   Node* etrue = effect;
@@ skipping 1557 matching lines @@
         isolate(), graph()->zone(), callable.descriptor(), 0, flags,
         Operator::kEliminatable);
     to_number_operator_.set(common()->Call(desc));
   }
   return to_number_operator_.get();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8