Does llvm support input Constraints

Hello,
within my architecture i have an instruction were two of its input
should be the same , something like:
operation src0,src1, src2,dst0
and src0=src1
i know that clang support inout Constraints
for example:
operation src0,src1,src2,dst0
and src0=dst0
by using in the td file let Constraints = “$src0 = $dst0”.

does llvm support inputs Constraints ?
mean let Constraints = “$src0 = $src1”.

Thanks all!