After setting 'guessInstructionProperties = 0', mayLoad, mayStore and hasSideEffects have been set to 0 per default in InstSystemZ.
Then those flags have been set on individual instructions so that there is no diff on the tablegen output compared to trunk.
I suspect that null_fag may have set this flag earlier in places where we could now remove it.
Not sure why, but SRAK seems to have the SideEffects flag...
hasSideEffects = 0 could also be removed in a few places.
This shouldn't have hasSideEffects = 1, but rather mayLoad = 1. This would fix a current bug.
Note that the whole block of load instructions really should have mayLoad = 1.