Found by inspecting AMDGPU assembly - so the arithmetic ops created there were definitely making their way into the target ISA. A `LLVM::BitcastOp` seems equivalent, and evaporates as expected in the target asm. Along the way, I thought that this helper function `mfmaConcatIfNeeded` could be renamed to `convertMFMAVectorOperand` to better convey its contract; so I don't need to think about whether a bitcast is a legitimate "concat" :-) --------- Signed-off-by: Benoit Jacob <jacob.benoit.1@gmail.com>