aco: don't create DPP instructions with SGPR operands

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Fixes: 2e6834d4f6 ("aco: combine DPP into VALU before RA")
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13976>

src/amd/compiler/aco_ir.cpp

@@ -318,6 +318,8 @@ can_use_DPP(const aco_ptr<Instruction>& instr, bool pre_ra)
          return false;
       if (instr->format == Format::VOP3)
          return false;
+      if (instr->operands.size() > 1 && !instr->operands[1].isOfType(RegType::vgpr))
+         return false;
    }
 
    /* there are more cases but those all take 64-bit inputs */