https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88481
--- Comment #4 from Heinrich Seebauer <heinrich.seebauer at swistec dot de> --- To isolate the cause, I suppressed several optimization options from thge -O1 group. Adding -fno-if-conversion to the options got the code correct, other -O1 options didn't change anything. I think, this is some strong evidence that -fif-conversion causes the bug. Proposed workaround: use option "-fno-if-conversion" in combination with -O1.
