Small addition to clarify: (insn 8) from the example is of course matched to a vzero. The "problem" begins when (reg 64) is later moved into another register and the (const_vector) has been optimized to a single definition e.g. by CSE, i.e. we have several
(insn yy (set (reg:V2DI xx) (reg:V2DI 64 [zero])) where (reg 64) is equivalent to a (const_vector 0). Regards Robin
