If we didn't set the value for hasSideEffects bit in our td file, llvm-tblgen will set it as true for those instructions which has no match pattern.
Below 6 instructions don't set the hasSideEffects flag and don't have match pattern, so their hasSideEffects flag will be set true by llvm-tblgen.
But in fact below instructions don't modify any special register and don't have other SideEffects, they shouldn't have SideEffects.
This patch is to modify the hasSideEffects of below instructions from 1 to 0.
VEXTUHLX VEXTUHRX VEXTUWLX VEXTUWRX VSPLTBs VSPLTHs