[turbofan] Various fixes to allow unboxed doubles as arguments in registers and on the stack.

test/cctest/compiler/c-signature.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_C_SIGNATURE_H_
 #define V8_COMPILER_C_SIGNATURE_H_
 
 #include "src/compiler/machine-type.h"
 
 namespace v8 {
@@ skipping 51 matching lines @@
                             MachineTypeForC<P5>()};
     for (int p = kMax - 1; p >= 0; p--) {
       if (p < static_cast<int>(parameter_count())) {
         CHECK_EQ(GetParam(p), params[p]);
       } else {
         CHECK_EQ(kMachNone, params[p]);
       }
     }
   }
 
+  static CSignature* FromMachine(Zone* zone, MachineSignature* msig) {
+    return reinterpret_cast<CSignature*>(msig);
+  }
+
   static CSignature* New(Zone* zone, MachineType ret,
                          MachineType p1 = kMachNone, MachineType p2 = kMachNone,
                          MachineType p3 = kMachNone, MachineType p4 = kMachNone,
                          MachineType p5 = kMachNone) {
     MachineType* buffer = zone->NewArray<MachineType>(6);
     int pos = 0;
     size_t return_count = 0;
     if (ret != kMachNone) {
       buffer[pos++] = ret;
       return_count++;
@@ skipping 71 matching lines @@
 typedef CSignature2<int32_t, int32_t, int32_t> CSignature_i_ii;
 typedef CSignature2<uint32_t, uint32_t, uint32_t> CSignature_u_uu;
 typedef CSignature2<float, float, float> CSignature_f_ff;
 typedef CSignature2<double, double, double> CSignature_d_dd;
 typedef CSignature2<Object*, Object*, Object*> CSignature_o_oo;
 }
 }
 }  // namespace v8::internal::compiler
 
 #endif  // V8_COMPILER_C_SIGNATURE_H_