[turbofan] Add support for reinterpreting integers as floating point and vice versa.

src/compiler/x64/code-generator-x64.cc

 // Copyright 2013 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/code-generator.h"
 
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/osr.h"
@@ skipping 1153 matching lines @@
       break;
     case kX64Movsd:
       if (instr->HasOutput()) {
         __ movsd(i.OutputDoubleRegister(), i.MemoryOperand());
       } else {
         size_t index = 0;
         Operand operand = i.MemoryOperand(&index);
         __ movsd(operand, i.InputDoubleRegister(index));
       }
       break;
+    case kX64BitcastFI:
+      if (instr->InputAt(0)->IsDoubleStackSlot()) {
+        __ movl(i.OutputRegister(), i.InputOperand(0));
+      } else {
+        __ movd(i.OutputRegister(), i.InputDoubleRegister(0));
+      }
+      break;
+    case kX64BitcastDL:
+      if (instr->InputAt(0)->IsDoubleStackSlot()) {
+        __ movq(i.OutputRegister(), i.InputOperand(0));
+      } else {
+        __ movq(i.OutputRegister(), i.InputDoubleRegister(0));
+      }
+      break;
+    case kX64BitcastIF:
+      if (instr->InputAt(0)->IsRegister()) {
+        __ movd(i.OutputDoubleRegister(), i.InputRegister(0));
+      } else {
+        __ movss(i.OutputDoubleRegister(), i.InputOperand(0));
+      }
+      break;
+    case kX64BitcastLD:
+      if (instr->InputAt(0)->IsRegister()) {
+        __ movq(i.OutputDoubleRegister(), i.InputRegister(0));
+      } else {
+        __ movsd(i.OutputDoubleRegister(), i.InputOperand(0));
+      }
+      break;
     case kX64Lea32: {
       AddressingMode mode = AddressingModeField::decode(instr->opcode());
       // Shorten "leal" to "addl", "subl" or "shll" if the register allocation
       // and addressing mode just happens to work out. The "addl"/"subl" forms
       // in these cases are faster based on measurements.
       if (i.InputRegister(0).is(i.OutputRegister())) {
         if (mode == kMode_MRI) {
           int32_t constant_summand = i.InputInt32(1);
           if (constant_summand > 0) {
             __ addl(i.OutputRegister(), Immediate(constant_summand));
@@ skipping 594 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace compiler
 }  // namespace v8