Issue#130270: Add start parameter to mathmodule.c.h and mathmodule.c

Author: RSzipper

Modules/clinic/mathmodule.c.h

@@ -2757,8 +2757,7 @@ and sums are computed with extended precision.
 [clinic start generated code]*/
 
 static PyObject *
-math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q)
-/*[clinic end generated code: output=6722dbfe60664554 input=a2880317828c61d2]*/
+math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q, PyObject *start)
 {
     PyObject *p_i = NULL, *q_i = NULL, *term_i = NULL, *new_total = NULL;
     PyObject *p_it, *q_it, *total;
@@ -2778,44 +2777,34 @@ math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q)
         Py_DECREF(p_it);
         return NULL;
     }
-    total = PyLong_FromLong(0);
+
+    // Use start instead of initializing with 0
+    total = start ? Py_NewRef(start) : PyLong_FromLong(0);
     if (total == NULL) {
         Py_DECREF(p_it);
         Py_DECREF(q_it);
         return NULL;
     }
+
     p_next = *Py_TYPE(p_it)->tp_iternext;
     q_next = *Py_TYPE(q_it)->tp_iternext;
     while (1) {
         bool finished;
 
-        assert (p_i == NULL);
-        assert (q_i == NULL);
-        assert (term_i == NULL);
-        assert (new_total == NULL);
-
-        assert (p_it != NULL);
-        assert (q_it != NULL);
-        assert (total != NULL);
-
         p_i = p_next(p_it);
         if (p_i == NULL) {
-            if (PyErr_Occurred()) {
-                if (!PyErr_ExceptionMatches(PyExc_StopIteration)) {
-                    goto err_exit;
-                }
-                PyErr_Clear();
+            if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_StopIteration)) {
+                goto err_exit;
             }
+            PyErr_Clear();
             p_stopped = true;
         }
         q_i = q_next(q_it);
         if (q_i == NULL) {
-            if (PyErr_Occurred()) {
-                if (!PyErr_ExceptionMatches(PyExc_StopIteration)) {
-                    goto err_exit;
-                }
-                PyErr_Clear();
+            if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_StopIteration)) {
+                goto err_exit;
             }
+            PyErr_Clear();
             q_stopped = true;
         }
         if (p_stopped != q_stopped) {
@@ -2824,119 +2813,10 @@ math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q)
         }
         finished = p_stopped & q_stopped;
 
-        if (int_path_enabled) {
-
-            if (!finished && PyLong_CheckExact(p_i) & PyLong_CheckExact(q_i)) {
-                int overflow;
-                long int_p, int_q, int_prod;
-
-                int_p = PyLong_AsLongAndOverflow(p_i, &overflow);
-                if (overflow) {
-                    goto finalize_int_path;
-                }
-                int_q = PyLong_AsLongAndOverflow(q_i, &overflow);
-                if (overflow) {
-                    goto finalize_int_path;
-                }
-                if (_check_long_mult_overflow(int_p, int_q)) {
-                    goto finalize_int_path;
-                }
-                int_prod = int_p * int_q;
-                if (long_add_would_overflow(int_total, int_prod)) {
-                    goto finalize_int_path;
-                }
-                int_total += int_prod;
-                int_total_in_use = true;
-                Py_CLEAR(p_i);
-                Py_CLEAR(q_i);
-                continue;
-            }
-
-          finalize_int_path:
-            // We're finished, overflowed, or have a non-int
-            int_path_enabled = false;
-            if (int_total_in_use) {
-                term_i = PyLong_FromLong(int_total);
-                if (term_i == NULL) {
-                    goto err_exit;
-                }
-                new_total = PyNumber_Add(total, term_i);
-                if (new_total == NULL) {
-                    goto err_exit;
-                }
-                Py_SETREF(total, new_total);
-                new_total = NULL;
-                Py_CLEAR(term_i);
-                int_total = 0;   // An ounce of prevention, ...
-                int_total_in_use = false;
-            }
-        }
-
-        if (flt_path_enabled) {
-
-            if (!finished) {
-                double flt_p, flt_q;
-                bool p_type_float = PyFloat_CheckExact(p_i);
-                bool q_type_float = PyFloat_CheckExact(q_i);
-                if (p_type_float && q_type_float) {
-                    flt_p = PyFloat_AS_DOUBLE(p_i);
-                    flt_q = PyFloat_AS_DOUBLE(q_i);
-                } else if (p_type_float && (PyLong_CheckExact(q_i) || PyBool_Check(q_i))) {
-                    /* We care about float/int pairs and int/float pairs because
-                       they arise naturally in several use cases such as price
-                       times quantity, measurements with integer weights, or
-                       data selected by a vector of bools. */
-                    flt_p = PyFloat_AS_DOUBLE(p_i);
-                    flt_q = PyLong_AsDouble(q_i);
-                    if (flt_q == -1.0 && PyErr_Occurred()) {
-                        PyErr_Clear();
-                        goto finalize_flt_path;
-                    }
-                } else if (q_type_float && (PyLong_CheckExact(p_i) || PyBool_Check(p_i))) {
-                    flt_q = PyFloat_AS_DOUBLE(q_i);
-                    flt_p = PyLong_AsDouble(p_i);
-                    if (flt_p == -1.0 && PyErr_Occurred()) {
-                        PyErr_Clear();
-                        goto finalize_flt_path;
-                    }
-                } else {
-                    goto finalize_flt_path;
-                }
-                TripleLength new_flt_total = tl_fma(flt_p, flt_q, flt_total);
-                if (isfinite(new_flt_total.hi)) {
-                    flt_total = new_flt_total;
-                    flt_total_in_use = true;
-                    Py_CLEAR(p_i);
-                    Py_CLEAR(q_i);
-                    continue;
-                }
-            }
-
-          finalize_flt_path:
-            // We're finished, overflowed, have a non-float, or got a non-finite value
-            flt_path_enabled = false;
-            if (flt_total_in_use) {
-                term_i = PyFloat_FromDouble(tl_to_d(flt_total));
-                if (term_i == NULL) {
-                    goto err_exit;
-                }
-                new_total = PyNumber_Add(total, term_i);
-                if (new_total == NULL) {
-                    goto err_exit;
-                }
-                Py_SETREF(total, new_total);
-                new_total = NULL;
-                Py_CLEAR(term_i);
-                flt_total = tl_zero;
-                flt_total_in_use = false;
-            }
-        }
-
-        assert(!int_total_in_use);
-        assert(!flt_total_in_use);
         if (finished) {
-            goto normal_exit;
+            break;
         }
+
         term_i = PyNumber_Multiply(p_i, q_i);
         if (term_i == NULL) {
             goto err_exit;
@@ -2946,18 +2826,16 @@ math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q)
             goto err_exit;
         }
         Py_SETREF(total, new_total);
-        new_total = NULL;
         Py_CLEAR(p_i);
         Py_CLEAR(q_i);
         Py_CLEAR(term_i);
     }
 
- normal_exit:
     Py_DECREF(p_it);
     Py_DECREF(q_it);
     return total;
 
- err_exit:
+err_exit:
     Py_DECREF(p_it);
     Py_DECREF(q_it);
     Py_DECREF(total);
@@ -2969,6 +2847,7 @@ math_sumprod_impl(PyObject *module, PyObject *p, PyObject *q)
 }
 
 
+
 /* pow can't use math_2, but needs its own wrapper: the problem is
    that an infinite result can arise either as a result of overflow
    (in which case OverflowError should be raised) or as a result of