MIPS: [turbofan] Combine ChangeFloat64ToInt32 with Float64Round ops.

src/compiler/mips/instruction-selector-mips.cc

 // Copyright 2014 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/base/adapters.h"
 #include "src/base/bits.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
@@ skipping 469 matching lines @@
   VisitRR(this, kMipsCvtDW, node);
 }
 
 
 void InstructionSelector::VisitChangeUint32ToFloat64(Node* node) {
   VisitRR(this, kMipsCvtDUw, node);
 }
 
 
 void InstructionSelector::VisitChangeFloat64ToInt32(Node* node) {
+  MipsOperandGenerator g(this);
+  Node* value = node->InputAt(0);
+  // Match ChangeFloat64ToInt32(Float64Round##OP) to corresponding instruction
+  // which does rounding and conversion to integer format.
+  if (CanCover(node, value)) {
+    switch (value->opcode()) {
+      case IrOpcode::kFloat64RoundDown:
+        Emit(kMipsFloorWD, g.DefineAsRegister(node),
+             g.UseRegister(value->InputAt(0)));
+        return;
+      case IrOpcode::kFloat64RoundUp:
+        Emit(kMipsCeilWD, g.DefineAsRegister(node),
+             g.UseRegister(value->InputAt(0)));
+        return;
+      case IrOpcode::kFloat64RoundTiesEven:
+        Emit(kMipsRoundWD, g.DefineAsRegister(node),
+             g.UseRegister(value->InputAt(0)));
+        return;
+      case IrOpcode::kFloat64RoundTruncate:
+        Emit(kMipsTruncWD, g.DefineAsRegister(node),
+             g.UseRegister(value->InputAt(0)));
+        return;
+      default:
+        VisitRR(this, kMipsTruncWD, node);
+        return;
+    }
+  }
   VisitRR(this, kMipsTruncWD, node);
 }
 
 
 void InstructionSelector::VisitChangeFloat64ToUint32(Node* node) {
   VisitRR(this, kMipsTruncUwD, node);
 }
 
 
 void InstructionSelector::VisitTruncateFloat64ToFloat32(Node* node) {
@@ skipping 726 matching lines @@
          MachineOperatorBuilder::kFloat32Max |
          MachineOperatorBuilder::kFloat32RoundDown |
          MachineOperatorBuilder::kFloat32RoundUp |
          MachineOperatorBuilder::kFloat32RoundTruncate |
          MachineOperatorBuilder::kFloat32RoundTiesEven;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8