Removed static type inference and add a dynamic test for string addition.

src/x64/virtual-frame-x64.cc

Index: src/x64/virtual-frame-x64.cc
diff --git a/src/x64/virtual-frame-x64.cc b/src/x64/virtual-frame-x64.cc
index e0b16e6c9cf8ded29600c132a354a9aaa9d8c8c9..312dccd499a3a8fba7d99cb10b1e96347b752294 100644
--- a/src/x64/virtual-frame-x64.cc
+++ b/src/x64/virtual-frame-x64.cc
@@ -433,7 +433,6 @@ void VirtualFrame::MakeMergable() {
         }
       }
       // No need to set the copied flag---there are no copies.

[Erik Corry, 2009/06/24 11:46:35]

The comment here doesn't match the comment in the IA32 version.  That makes it
hard to diff them.

-      elements_[i].set_static_type(StaticType::unknown());
     } else {
       // Clear the copy flag of non-constant, non-copy elements.
       // They cannot be copied because copies are not allowed.
@@ -651,7 +650,6 @@ Result VirtualFrame::Pop() {
     if (element.is_memory()) {
       Result temp = cgen()->allocator()->Allocate();
       ASSERT(temp.is_valid());
-      temp.set_static_type(element.static_type());
       __ pop(temp.reg());
       return temp;
     }
@@ -683,12 +681,11 @@ Result VirtualFrame::Pop() {
         FrameElement::RegisterElement(temp.reg(), FrameElement::SYNCED);
     // Preserve the copy flag on the element.
     if (element.is_copied()) new_element.set_copied();
-    new_element.set_static_type(element.static_type());
     elements_[index] = new_element;
     __ movq(temp.reg(), Operand(rbp, fp_relative(index)));
-    return Result(temp.reg(), element.static_type());
+    return Result(temp.reg());
   } else if (element.is_register()) {
-    return Result(element.reg(), element.static_type());
+    return Result(element.reg());
   } else {
     ASSERT(element.is_constant());
     return Result(element.handle());