Avoid undefined behavior of left shifting negative integer; #3728

cc01dedc · Yukihiro "Matz" Matsumoto · c377d504 · cc01dedc
Commit cc01dedc authored Jul 05, 2017 by Yukihiro "Matz" Matsumoto
Show whitespace changes
Inline Side-by-side

Showing with 2 additions and 2 deletions

src/numeric.c src/numeric.c +2 -2

No files found.
--- a/src/numeric.c
+++ b/src/numeric.c
@@ -962,16 +962,16 @@ lshift(mrb_state *mrb, mrb_int val, mrb_int width)
        (val   > (MRB_INT_MAX >> width))) {
      goto bit_overflow;
    }
+    return mrb_fixnum_value(val << width);
  }
  else {
    if ((width > NUMERIC_SHIFT_WIDTH_MAX) ||
        (val   < (MRB_INT_MIN >> width))) {
      goto bit_overflow;
    }
+    return mrb_fixnum_value(val * (1u << width));
  }

-  return mrb_fixnum_value(val << width);
-
 bit_overflow:
  {
    mrb_float f = (mrb_float)val;