Replace OS::MemCopy with OS::MemMove (just as fast but more flexible).

src/ia32/assembler-ia32.h

Index: src/ia32/assembler-ia32.h
diff --git a/src/ia32/assembler-ia32.h b/src/ia32/assembler-ia32.h
index a3da9af43362dd37176d2df7767e1cff263ceb35..d1c1fbf00389acb2b99ef3c552ef578e2131f35a 100644
--- a/src/ia32/assembler-ia32.h
+++ b/src/ia32/assembler-ia32.h
@@ -1026,6 +1026,13 @@ class Assembler : public AssemblerBase {
   void movdqa(const Operand& dst, XMMRegister src);
   void movdqu(XMMRegister dst, const Operand& src);
   void movdqu(const Operand& dst, XMMRegister src);
+  void movdq(bool aligned, XMMRegister dst, const Operand& src) {
+    if (aligned) {
+      movdqa(dst, src);
+    } else {
+      movdqu(dst, src);
+    }
+  }
 
   // Use either movsd or movlpd.
   void movdbl(XMMRegister dst, const Operand& src);