https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102767
--- Comment #5 from Richard Earnshaw <rearnsha at gcc dot gnu.org> --- We have the type <vector_type 0x7ffff758c9d8 type <integer_type 0x7ffff7517bd0 public unsigned TI size <integer_cst 0x7ffff7514ee8 constant 128> unit-size <integer_cst 0x7ffff7514f00 constant 16> and movmisalign pattern is enabled for this. but the vectorization cost doesn't handle the case of elements=1, which is the case when mode is TImode. So I think this is an inconsistency in the rs6000 backend - either add costing support for single elements or disable the movmisalign code in this case.