UBSan: Undefined Behavior in /public/src.git/lib/libc/stdlib/jemalloc.c:1707:14, left shift of 1 by 31 places cannot be represented in type 'int'

        mask = run->regs_mask[i];
        if (mask != 0) {
                /* Usable allocation found. */
                bit = ffs((int)mask) - 1;

                regind = ((i << (SIZEOF_INT_2POW + 3)) + bit);
                ret = (void *)(((uintptr_t)run) + bin->reg0_offset
                    + (bin->reg_size * regind));

                /* Clear bit. */
                mask ^= (1 << bit); //// <--- here
                run->regs_mask[i] = mask;

                return (ret);
        }

UBSan: Undefined Behavior in /public/src.git/lib/libc/stdlib/jemalloc.c:1840:28, left shift of 1 by 31 places cannot be represented in type 'int'
UBSan: Undefined Behavior in /public/src.git/lib/libc/stdlib/jemalloc.c:1724:15, left shift of 1 by 31 places cannot be represented in type 'int'