mgather expand error

Hello,

my target support maximum gather of v64i32…i want to lower all the greater gathers to v64i32. for this i used;

setOperationAction(ISD::MGATHER, MVT::v128i32, Expand);

but i am getting error;

LLVM ERROR: Cannot select: t4257: v128i32,ch = masked_gather<LD512(tbaa=<0x30e7c78>)> t0, undef:v128i32, t4394, TargetConstant:i64<0>, t4312
t1061: v128i32 = undef
t4394: v128i1 = BUILD_VECTOR TargetConstant:i1<-1>, TargetConstant:i1<-1>, TargetConstant:i1<-1>, TargetConstant:i1<-1>,…

why is that so?

please help?