Always 64-bit align floating point values in heap numbers....

src/ia32/macro-assembler-ia32.h

Index: src/ia32/macro-assembler-ia32.h
===================================================================
--- src/ia32/macro-assembler-ia32.h	(revision 3405)
+++ src/ia32/macro-assembler-ia32.h	(working copy)
@@ -278,6 +278,16 @@
                                Register scratch,
                                Label* miss);
 
+  // The double precision value in a heap number is always aligned even
+  // if the heap number object isn't.  This takes the address of a heap
+  // number and puts the address of its value in the result register.
+  // It is OK for the two registers to be identical.
+  void GenerateHeapNumberValueAddress(Register result, Register number) {
+    lea(result, Operand(number, 4 + HeapNumber::kValueMinimumOffset - kHeapObjectTag));
+    and_(result, -8);
+    //lea(result, Operand(number, HeapNumber::kValueMinimumOffset - kHeapObjectTag));
+  }
+
   // Generates code for reporting that an illegal operation has
   // occurred.
   void IllegalOperation(int num_arguments);