WIP: i965/fs: Merge CMP and SEL into CSEL on Gen8+
It doesn't work for type-converting MOVs because
f > 0is not the same as
f2i(f) > 0
CSELis a 3src instruction and only supports one source type; it doesn't take this into account and tries to create instructions which do a F compare and a D select. This is especially nasty to debug because you don't see that in the dumped assembly because we don't properly assert that types are the same in codegen.
While you can handle 2, in theory, by reinterpreting types, you can't do that in the presence of source modifiers. This pass doesn't even attempt to detect that.
Hopefully having an MR outstanding will help us remember to fix it one day.