c_encoding can never be NULL, which allows some code simplification

Python/ast.c

@@ -4002,55 +4002,52 @@ decode_unicode(struct compiling *c, const char *s, size_t len, const char *encod
     char *p;
     const char *end;
 
-    if (encoding == NULL) {
-        u = NULL;
-    } else {
-        /* check for integer overflow */
-        if (len > PY_SIZE_MAX / 6)
-            return NULL;
-        /* "ä" (2 bytes) may become "\U000000E4" (10 bytes), or 1:5
-           "\ä" (3 bytes) may become "\u005c\U000000E4" (16 bytes), or ~1:6 */
-        u = PyBytes_FromStringAndSize((char *)NULL, len * 6);
-        if (u == NULL)
-            return NULL;
-        p = buf = PyBytes_AsString(u);
-        end = s + len;
-        while (s < end) {
-            if (*s == '\\') {
-                *p++ = *s++;
-                if (*s & 0x80) {
-                    strcpy(p, "u005c");
-                    p += 5;
-                }
+    /* check for integer overflow */
+    if (len > PY_SIZE_MAX / 6)
+        return NULL;
+    /* "ä" (2 bytes) may become "\U000000E4" (10 bytes), or 1:5
+       "\ä" (3 bytes) may become "\u005c\U000000E4" (16 bytes), or ~1:6 */
+    u = PyBytes_FromStringAndSize((char *)NULL, len * 6);
+    if (u == NULL)
+        return NULL;
+    p = buf = PyBytes_AsString(u);
+    end = s + len;
+    while (s < end) {
+        if (*s == '\\') {
+            *p++ = *s++;
+            if (*s & 0x80) {
+                strcpy(p, "u005c");
+                p += 5;
             }
-            if (*s & 0x80) { /* XXX inefficient */
-                PyObject *w;
-                int kind;
-                void *data;
-                Py_ssize_t len, i;
-                w = decode_utf8(c, &s, end);
-                if (w == NULL) {
-                    Py_DECREF(u);
-                    return NULL;
-                }
-                kind = PyUnicode_KIND(w);
-                data = PyUnicode_DATA(w);
-                len = PyUnicode_GET_LENGTH(w);
-                for (i = 0; i < len; i++) {
-                    Py_UCS4 chr = PyUnicode_READ(kind, data, i);
-                    sprintf(p, "\\U%08x", chr);
-                    p += 10;
-                }
-                /* Should be impossible to overflow */
-                assert(p - buf <= Py_SIZE(u));
-                Py_DECREF(w);
-            } else {
-                *p++ = *s++;
+        }
+        if (*s & 0x80) { /* XXX inefficient */
+            PyObject *w;
+            int kind;
+            void *data;
+            Py_ssize_t len, i;
+            w = decode_utf8(c, &s, end);
+            if (w == NULL) {
+                Py_DECREF(u);
+                return NULL;
             }
+            kind = PyUnicode_KIND(w);
+            data = PyUnicode_DATA(w);
+            len = PyUnicode_GET_LENGTH(w);
+            for (i = 0; i < len; i++) {
+                Py_UCS4 chr = PyUnicode_READ(kind, data, i);
+                sprintf(p, "\\U%08x", chr);
+                p += 10;
+            }
+            /* Should be impossible to overflow */
+            assert(p - buf <= Py_SIZE(u));
+            Py_DECREF(w);
+        } else {
+            *p++ = *s++;
         }
-        len = p - buf;
-        s = buf;
     }
+    len = p - buf;
+    s = buf;
+
     v = PyUnicode_DecodeUnicodeEscape(s, len, NULL);
     Py_XDECREF(u);
     return v;
@@ -4994,8 +4991,7 @@ parsestr(struct compiling *c, const node *n, int *bytesmode, int *fmode)
             }
         }
     }
-    need_encoding = (!*bytesmode && c->c_encoding != NULL &&
-                     strcmp(c->c_encoding, "utf-8") != 0);
+    need_encoding = !*bytesmode && strcmp(c->c_encoding, "utf-8") != 0;
     if (rawmode || strchr(s, '\\') == NULL) {
         if (need_encoding) {
             PyObject *v, *u = PyUnicode_DecodeUTF8(s, len, NULL);