Initial real implementation of simple merge for frames. Does not yet...

src/register-allocator-ia32.cc

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 23 matching lines @@
 
 void RegisterAllocator::Initialize() {
   registers_.Reset();
   registers_.Use(esp);
   registers_.Use(ebp);
   registers_.Use(esi);
   registers_.Use(edi);
 }
 
 
-Register RegisterAllocator::Allocate() {
+Register RegisterAllocator::AllocateWithoutSpilling() {
   // Return the first free register, if any.
   for (int i = 0; i < num_registers(); i++) {
     if (!registers_.is_used(i)) {
       Register result = { i };
       registers_.Use(result);
       return result;
     }
   }
+  return no_reg;
+}
 
-  // Ask the current frame to spill a register.
-  ASSERT(code_generator_->frame() != NULL);
-  Register result = code_generator_->frame()->SpillAnyRegister();
-  if (!result.is(no_reg)) {
-    ASSERT(!registers_.is_used(result.code()));
-    registers_.Use(result);
+
+Register RegisterAllocator::Allocate() {
+  Register result = AllocateWithoutSpilling();
+  if (result.is(no_reg)) {
+    // Ask the current frame to spill a register.
+    ASSERT(code_generator_->frame() != NULL);
+    result = code_generator_->frame()->SpillAnyRegister();
+    if (!result.is(no_reg)) {
+      ASSERT(!registers_.is_used(result.code()));
+      registers_.Use(result);
+    }
   }
-
   return result;
 }
 
 
 } }  // namespace v8::internal