diff --git a/src/lj_intrinsic.c b/src/lj_intrinsic.c
index c5ee7a94..845e0e62 100644
--- a/src/lj_intrinsic.c
+++ b/src/lj_intrinsic.c
@@ -780,6 +780,8 @@ int lj_intrinsic_fromcdef(lua_State *L, CTypeID fid, GCstr *opstr, uint32_t imm)
       /* Use opcode unmodified in its SSE form */
       intrins->flags &= ~INTRINSFLAG_VEX;
     }
+  } else if(!LJ_64 && (intrins->flags & INTRINSFLAG_REXW)) {
+    intrins->flags &= ~INTRINSFLAG_REXW;
   }
 #endif
 
diff --git a/tests/intrinsic_spec.lua b/tests/intrinsic_spec.lua
index 563209b0..eacf94a5 100644
--- a/tests/intrinsic_spec.lua
+++ b/tests/intrinsic_spec.lua
@@ -429,7 +429,7 @@ context("__mcode", function()
   end) 
   
   it("output pointers", function() 
-    assert_cdef([[const char* addptr(const char* nptr, int32_t n) __mcode("03rM");]], "addptr")
+    assert_cdef([[const char* addptr(const char* nptr, int32_t n) __mcode("03rMX");]], "addptr")
     local s = "0123456789abcdefghijklmnopqrstvwxyz"
     
     local ptr = ffi.C.addptr(s, 0)