check PyLong_AsLongAndOverflow result for error

Author: WolframAlph

Python/flowgraph.c

@@ -1387,21 +1387,28 @@ nop_out(cfg_instr **instrs, int size)
     }
 }
 
-/* Does not steal reference to "newconst" */
-static bool
+/* Does not steal reference to "newconst".
+   Return 1 if changed instruction to LOAD_SMALL_INT.
+   Return 0 if could not change instruction to LOAD_SMALL_INT.
+   Return -1 on error.
+*/
+static int
 maybe_instr_make_load_smallint(cfg_instr *instr, PyObject *newconst,
                                PyObject *consts, PyObject *const_cache)
 {
     if (PyLong_CheckExact(newconst)) {
         int overflow;
         long val = PyLong_AsLongAndOverflow(newconst, &overflow);
+        if (val == -1 && PyErr_Occurred()) {
+            return -1;
+        }
         if (!overflow && _PY_IS_SMALL_INT(val)) {
             assert(_Py_IsImmortal(newconst));
             INSTR_SET_OP1(instr, LOAD_SMALL_INT, (int)val);
-            return true;
+            return 1;
         }
     }
-    return false;
+    return 0;
 }
 
 
@@ -1410,9 +1417,9 @@ static int
 instr_make_load_const(cfg_instr *instr, PyObject *newconst,
                       PyObject *consts, PyObject *const_cache)
 {
-    if (maybe_instr_make_load_smallint(instr, newconst, consts, const_cache)) {
-        assert(instr->i_opcode == LOAD_SMALL_INT);
-        return SUCCESS;
+    int res = maybe_instr_make_load_smallint(instr, newconst, consts, const_cache);
+    if (res) {
+        return res == -1 ? ERROR : SUCCESS;
     }
     int oparg = add_const(newconst, consts, const_cache);
     RETURN_IF_ERROR(oparg);
@@ -2054,8 +2061,11 @@ basicblock_optimize_load_const(PyObject *const_cache, basicblock *bb, PyObject *
         cfg_instr *inst = &bb->b_instr[i];
         if (inst->i_opcode == LOAD_CONST) {
             PyObject *constant = get_const_value(inst->i_opcode, inst->i_oparg, consts);
-            (void)maybe_instr_make_load_smallint(inst, constant, consts, const_cache);
+            int res = maybe_instr_make_load_smallint(inst, constant, consts, const_cache);
             Py_DECREF(constant);
+            if (res < 0) {
+                return ERROR;
+            }
         }
         bool is_copy_of_load_const = (opcode == LOAD_CONST &&
                                       inst->i_opcode == COPY &&