X87: [turbofan] Add support for reinterpreting integers as floating point and vice versa.

src/compiler/x87/code-generator-x87.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 1051 matching lines @@
         DCHECK(output.code() == 0);
         __ fstp(0);
         __ fld_s(i.MemoryOperand());
       } else {
         size_t index = 0;
         Operand operand = i.MemoryOperand(&index);
         __ fst_s(operand);
       }
       break;
     }
+    case kX87BitcastFI: {
+      __ fstp(0);
+      __ mov(i.OutputRegister(), MemOperand(esp, 0));
+      __ lea(esp, Operand(esp, kFloatSize));
+      break;
+    }
+    case kX87BitcastIF: {
+      if (instr->InputAt(0)->IsRegister()) {
+        __ lea(esp, Operand(esp, -kFloatSize));
+        __ mov(MemOperand(esp, 0), i.InputRegister(0));
+        __ fstp(0);
+        __ fld_s(MemOperand(esp, 0));
+        __ lea(esp, Operand(esp, kFloatSize));
+      } else {
+        __ lea(esp, Operand(esp, -kDoubleSize));
+        __ mov(MemOperand(esp, 0), i.InputRegister(0));
+        __ fstp(0);
+        __ fld_d(MemOperand(esp, 0));
+        __ lea(esp, Operand(esp, kDoubleSize));
+      }
+      break;
+    }
     case kX87Lea: {
       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 (mode == kMode_MI) {
         __ Move(i.OutputRegister(), Immediate(i.InputInt32(0)));
       } else if (i.InputRegister(0).is(i.OutputRegister())) {
         if (mode == kMode_MRI) {
           int32_t constant_summand = i.InputInt32(1);
@@ skipping 772 matching lines @@
     int padding_size = last_lazy_deopt_pc_ + space_needed - current_pc;
     __ Nop(padding_size);
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8