diff --git a/src/car-cdr.c b/src/car-cdr.c
index 2e22968..ccb90ed 100644
--- a/src/car-cdr.c
+++ b/src/car-cdr.c
@@ -78,6 +78,7 @@ LispPTR car(register LispPTR datum)
       return (NIL);
     else
       error("car : ARG not list");
+    return (NIL); /* NOT REACHED */
   }
 } /* end of car */
 
@@ -150,6 +151,7 @@ LispPTR rplaca(register LispPTR x, register LispPTR y)
         return (NIL_PTR);
     } else
       error("ARG not List");
+      return (NIL_PTR); /* NOT REACHED */
   }
 
   else {
diff --git a/src/gchtfind.c b/src/gchtfind.c
index a6ad903..ac9332b 100644
--- a/src/gchtfind.c
+++ b/src/gchtfind.c
@@ -94,6 +94,7 @@
         IncAllocCnt(1);                                               \
         return ptr; /* new 0 entry */                                 \
       default: error("GC error: new entry touches stack bit");        \
+        return NIL; /* NOT REACHED */                                 \
     }                                                                 \
   }
 
@@ -114,6 +115,7 @@
         GETGC(entry) = hiptr | (1 << HTCNTSHIFT) | HTSTKMASK;           \
         return NIL;                                                     \
       default: error("GC error: new entry when turning off stack bit"); \
+        return NIL; /* NOT REACHED */                                   \
     }                                                                   \
   }
 
diff --git a/src/hardrtn.c b/src/hardrtn.c
index 855594d..d6a5bad 100644
--- a/src/hardrtn.c
+++ b/src/hardrtn.c
@@ -250,7 +250,8 @@ retry: /* this is retry entry after MAKE_FXCOPY etc */
     else
       error("Shouldn't");
   }
-
+  error("Control reached end of slowreturn()!");
+  return (NIL); /* NOT REACHED */
 } /* slowreturn end */
 
 #define MAXSAFEUSECOUNT 200