thanks for pointing out! I tried the borrowing trick from the previous segment, was pretty obvious, but for some reason failed as could not avoid at least one conditinonal... will try again.
For my problem describe under the link above the suggestions above eliminate indeed the branches, but same time the extra instructions slow down the same as my initial branches. Meaning, detecting newlines would work almost 100% of memory throughput, but detecting first non-space reduces the speed to bit above 50% of bandwith
Falvyu's and bremac's solution seems to be the best.