Remove unneeded overflow check in integer division

* src/data.c (arith_driver): Remove unnecessary runtime test,
since integer overflow is impossible on division of fixnums,
given that the worst case is MOST_NEGATIVE_FIXNUM / -1 which is
representable as an EMACS_INT (albeit not as a fixnum).

diff --git a/src/data.c b/src/data.c
index d968ac9e3a97d23eddab4b8acf1f1ff434d14307..955e50739008cc8eaea27dbb00dc9c481bcfcc47 100644 (file)
--- a/src/data.c
+++ b/src/data.c
@@ -2944,7 +2944,7 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args,
        /* Set ACCUM to the next operation's result if it fits,
           else exit the loop.  */
        bool overflow = false;
-       intmax_t a UNINIT;
+       intmax_t a;
        switch (code)
          {
          case Aadd : overflow = INT_ADD_WRAPV (accum, next, &a); break;
@@ -2953,9 +2953,8 @@ arith_driver (enum arithop code, ptrdiff_t nargs, Lisp_Object *args,
          case Adiv:
            if (next == 0)
              xsignal0 (Qarith_error);
-           overflow = INT_DIVIDE_OVERFLOW (accum, next);
-           if (!overflow)
-             a = accum / next;
+           eassert (! INT_DIVIDE_OVERFLOW (accum, next));
+           a = accum / next;
            break;
          case Alogand: accum &= next; continue;
          case Alogior: accum |= next; continue;