diff --git a/C/errors.c b/C/errors.c
index 105a38358..c4491fe4f 100755
--- a/C/errors.c
+++ b/C/errors.c
@@ -551,7 +551,6 @@ static char tmpbuf[YAP_BUF_SIZE];
 #include "YapErrors.h"
 
 bool Yap_pushErrorContext(bool pass, yap_error_descriptor_t *new_error) {
-    yap_error_number err = LOCAL_ActiveError->errorNo;
     memset(new_error, 0, sizeof(yap_error_descriptor_t));
     new_error->top_error = LOCAL_ActiveError;
     LOCAL_ActiveError = new_error;
@@ -1029,7 +1028,10 @@ static Int get_exception(USES_REGS1) {
     } else {
       t = mkerrort(i->errorNo, TermNil, MkSysError(i));
     }
-    return Yap_unify(t, ARG1);
+    while (B && B->cp_b && ! Yap_unify(t, B->cp_a2)) {
+      Yap_JumpToEnv();
+    }
+    return true;
   }
   return false;
 }
diff --git a/C/eval.c b/C/eval.c
index e9d6ef43d..9760112e8 100644
--- a/C/eval.c
+++ b/C/eval.c
@@ -148,8 +148,8 @@ static Term Eval(Term t USES_REGS) {
       }
       t2 = Eval(ArgOfTerm(2, t) PASS_REGS);
       *RepAppl(t) = (CELL)fun;
-        LOCAL_ctx = ctx.p;
-        return Yap_eval_binary(p->FOfEE, t1, t2);
+      LOCAL_ctx = ctx.p;
+      return Yap_eval_binary(p->FOfEE, t1, t2);
     }
   } /* else if (IsPairTerm(t)) */
   {
@@ -208,8 +208,8 @@ static Int p_is(USES_REGS1) { /* X is Y	 */
   }
   do {
     go = false;
-    out = Yap_InnerEval(Deref(ARG2));
-    Yap_CheckArithError();
+    out = Yap_Eval(t PASS_REGS);
+    go = Yap_CheckArithError();
   } while (go);
   return Yap_unify_constant(ARG1, out);
 }
diff --git a/H/YapEval.h b/H/YapEval.h
index e799a2288..82a578738 100644
--- a/H/YapEval.h
+++ b/H/YapEval.h
@@ -632,7 +632,7 @@ __Yap_Mk64IntegerTerm(YAP_LONG_LONG i USES_REGS) {
 }
 
 inline static Term add_int(Int i, Int j USES_REGS) {
-#if defined(__clang__)
+#if defined(__clang__) || defined(__GNUC__)
   Int w;
   if (!__builtin_add_overflow(i, j, &w))
     RINT(w);
diff --git a/H/arith2.h b/H/arith2.h
index e58eb0b20..51358f470 100755
--- a/H/arith2.h
+++ b/H/arith2.h
@@ -24,11 +24,13 @@ inline static int sub_overflow(Int x, Int i, Int j) {
 }
 
 inline static Term sub_int(Int i, Int j USES_REGS) {
-#if defined(__clang__)
-    Int w;
-    if (!__builtin_sub_overflow(i,j,&w))
-         RINT(w);
-    return Yap_gmp_add_ints(i, j);
+#if defined(__clang__ ) || defined(__GNUC__)
+    Int k;
+    if (__builtin_sub_overflow(i,j,&k)) {
+      return Yap_gmp_add_ints(i, j);
+    }
+    printf("%ld %ld %ld\n", i, j , k);
+    RINT(k);
 #elif defined(__GNUC__)
     Int w;
     if (!__builtin_sub_overflow_p(i,j,w))
diff --git a/pl/builtins.yap b/pl/builtins.yap
index fb72a19a6..39e695cfa 100644
--- a/pl/builtins.yap
+++ b/pl/builtins.yap
@@ -332,6 +332,7 @@ once(G) :-
 	'$meta_call'(C, M),
 	!.
 
+
 (:- G) :- '$execute'(G), !.
 
 (?- G) :- '$execute'(G).
diff --git a/pl/top.yap b/pl/top.yap
index 97dd34c0d..21333bf8f 100644
--- a/pl/top.yap
+++ b/pl/top.yap
@@ -965,10 +965,8 @@ catch(G, C, A) :-
   ).
 '$catch'(_,C,A) :-
 	'$get_exception'(C),
-	!,
-	'$run_catch'(A, C).
-'$catch'(_,_C,A) :-
-	throw(A).
+	%( C = C0 -> '$execute'(A) ; throw(A0) ).
+	'$run_catch'(C,A).
 
 % variable throws are user-handled.
 '$run_catch'(G,E) :-