[turbofan] Implemented the optional Float32RoundDown operator.

src/compiler/machine-operator.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/compiler/machine-operator.h"
 
 #include "src/base/lazy-instance.h"
 #include "src/compiler/opcodes.h"
 #include "src/compiler/operator.h"
 
@@ skipping 168 matching lines @@
 
 #define PURE_OPTIONAL_OP_LIST(V)                            \
   V(Word32Ctz, Operator::kNoProperties, 1, 0, 1)            \
   V(Word64Ctz, Operator::kNoProperties, 1, 0, 1)            \
   V(Word32Popcnt, Operator::kNoProperties, 1, 0, 1)         \
   V(Word64Popcnt, Operator::kNoProperties, 1, 0, 1)         \
   V(Float32Max, Operator::kNoProperties, 2, 0, 1)           \
   V(Float32Min, Operator::kNoProperties, 2, 0, 1)           \
   V(Float64Max, Operator::kNoProperties, 2, 0, 1)           \
   V(Float64Min, Operator::kNoProperties, 2, 0, 1)           \
+  V(Float32RoundDown, Operator::kNoProperties, 1, 0, 1)     \
   V(Float64RoundDown, Operator::kNoProperties, 1, 0, 1)     \
   V(Float64RoundUp, Operator::kNoProperties, 1, 0, 1)       \
   V(Float64RoundTruncate, Operator::kNoProperties, 1, 0, 1) \
   V(Float64RoundTiesAway, Operator::kNoProperties, 1, 0, 1) \
   V(Float64RoundTiesEven, Operator::kNoProperties, 1, 0, 1)
 
 
 #define MACHINE_TYPE_LIST(V) \
   V(MachFloat32)             \
   V(MachFloat64)             \
@@ skipping 208 matching lines @@
     default:
       break;
   }
   UNREACHABLE();
   return nullptr;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8