"Bingfeng Mei" <b...@broadcom.com> writes: > Could anyone explain to me what is difference between > vec_shl_<vector_mode> and ashl<vector_mode>3 patterns? It seems to me > that both shift a vector operand 1 with scalar operand 2.
The difference is that with a vector mode gcc will look for the standard name vec_shl_MODE, and with a non-vector mode gcc will look for the standard name lshlMODE or ashlMODE. > I tried to understand some targets' implemenation, e.g., ia64 as > follows, and cannot grasp their difference. The name which matters is vec_shr_<mode>. The fact that the ia64 names the real insn <lshr>mode3 does not imply that that insn name is actually used by anything. vec_shr_<mode> is a define_expand which is expands into a pattern which is recognized by the <lshr>mode3 insn. The name of the <lshr>mode3 insn could change or be removed and everything would work. Ian
