Generate some intrinsics using our IR.

runtime/vm/intermediate_language_arm64.cc

Index: runtime/vm/intermediate_language_arm64.cc
===================================================================
--- runtime/vm/intermediate_language_arm64.cc	(revision 39651)
+++ runtime/vm/intermediate_language_arm64.cc	(working copy)
@@ -61,7 +61,7 @@
     } else {
       ASSERT(value.IsStackSlot());
       const intptr_t value_offset = value.ToStackSlotOffset();
-      __ LoadFromOffset(TMP, FP, value_offset, PP);
+      __ LoadFromOffset(TMP, value.base_reg(), value_offset, PP);
       __ Push(TMP);
     }
   }
@@ -85,6 +85,13 @@
 void ReturnInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   const Register result = locs()->in(0).reg();
   ASSERT(result == R0);
+
+  if (is_intrinsic_) {
+    // Intrinsics don't have a frame.
+    __ ret();
+    return;
+  }
+
 #if defined(DEBUG)
   Label stack_ok;
   __ Comment("Stack Check");