diff --git a/src/gallium/drivers/r600/sfn/sfn_instr_alu.cpp b/src/gallium/drivers/r600/sfn/sfn_instr_alu.cpp
index 25f0663e9a0..e9de6fd66c6 100644
--- a/src/gallium/drivers/r600/sfn/sfn_instr_alu.cpp
+++ b/src/gallium/drivers/r600/sfn/sfn_instr_alu.cpp
@@ -537,6 +537,14 @@ bool AluInstr::do_replace_source(PRegister old_src, PVirtualValue new_src)
    return process;
 }
 
+void
+AluInstr::override_or_clear_dest(PRegister dummy_reg)
+{
+   m_alu_flags.reset(alu_write);
+   m_fallback_chan = m_dest->chan();
+   m_dest = m_src.size() < 3 ? nullptr : dummy_reg;
+}
+
 bool AluInstr::replace_src(int i, PVirtualValue new_src, uint32_t to_set,
                            SourceMod to_clear)
 {
diff --git a/src/gallium/drivers/r600/sfn/sfn_instr_alu.h b/src/gallium/drivers/r600/sfn/sfn_instr_alu.h
index 0d103b88956..e98cadddcc3 100644
--- a/src/gallium/drivers/r600/sfn/sfn_instr_alu.h
+++ b/src/gallium/drivers/r600/sfn/sfn_instr_alu.h
@@ -209,6 +209,8 @@ public:
    auto output_modifier() const { return m_output_modifier; }
    auto has_output_modifier() const { return m_output_modifier != omod_none; }
 
+   void override_or_clear_dest(PRegister dummy_reg);
+
 private:
    friend class AluGroup;