[teo_zero]

Except that arr[...] - value may overflow, and is UB in C.

Even removing the UB with something like __builtin_sub_overflow(), if arr[...] is INT_MAX and value is -2, then the difference will have the high bit set!

I haven't tried it, but this should compile to a cmove or seta, not a jump:

  int cond = arr[step+begin] < value;
  begin += step & -cond;

[yarg]

My bad, but still worth mentioning the generalised case:

    int mask = -(arr[step+begin] < value);
    int value = (val0 & mask)|(val1 & ~mask);