Add support for XMM registers in SSA code generation pipeline.

runtime/vm/il_printer.cc

Index: runtime/vm/il_printer.cc
diff --git a/runtime/vm/il_printer.cc b/runtime/vm/il_printer.cc
index 9908edbc02ee82273dd43ba652474be880b004f8..0ea5e448c655381a61bd979a4ea526a598b40b0f 100644
--- a/runtime/vm/il_printer.cc
+++ b/runtime/vm/il_printer.cc
@@ -397,6 +397,14 @@ void BinaryMintOpComp::PrintOperandsTo(BufferFormatter* f) const {
 }
 
 
+void UnboxedDoubleBinaryOpComp::PrintOperandsTo(BufferFormatter* f) const {
+  f->Print("%s, ", Token::Str(op_kind()));
+  left()->PrintTo(f);
+  f->Print(", ");
+  right()->PrintTo(f);
+}
+
+
 void BinaryDoubleOpComp::PrintOperandsTo(BufferFormatter* f) const {
   f->Print("%s", Token::Str(op_kind()));
 }