[turbofan] Add backend support for Float32Constant.

src/compiler/instruction-selector-unittest.h

 // 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.
 
 #ifndef V8_COMPILER_INSTRUCTION_SELECTOR_UNITTEST_H_
 #define V8_COMPILER_INSTRUCTION_SELECTOR_UNITTEST_H_
 
 #include <deque>
 #include <set>
 
@@ skipping 125 matching lines @@
       return !IsDouble(virtual_register) && !IsReference(virtual_register);
     }
 
     bool IsReference(const InstructionOperand* operand) const {
       return IsReference(ToVreg(operand));
     }
     bool IsReference(int virtual_register) const {
       return references_.find(virtual_register) != references_.end();
     }
 
+    float ToFloat32(const InstructionOperand* operand) const {
+      return ToConstant(operand).ToFloat32();
+    }
+
     int32_t ToInt32(const InstructionOperand* operand) const {
       return ToConstant(operand).ToInt32();
     }
 
     int64_t ToInt64(const InstructionOperand* operand) const {
       return ToConstant(operand).ToInt64();
     }
 
     int ToVreg(const InstructionOperand* operand) const {
       if (operand->IsConstant()) return operand->index();
@@ skipping 44 matching lines @@
 template <typename T>
 class InstructionSelectorTestWithParam
     : public InstructionSelectorTest,
       public ::testing::WithParamInterface<T> {};
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_INSTRUCTION_SELECTOR_UNITTEST_H_