WIP for scalar_mul_add

src/simplify_algebra.cpp

@@ -440,11 +440,44 @@ struct find_mul_add
         auto x_ins = r.instructions["x"];
         assert(x_ins != b_ins);
 
+        if(a_ins->get_shape().scalar())
+        {
+            return;
+        }
+
         auto ax_ins = m.insert_instruction(ins, make_op("mul"), a_ins, x_ins);
         auto ab_ins = m.insert_instruction(ins, make_op("mul"), a_ins, b_ins);
         m.replace_instruction(ins, make_op("add"), ax_ins, ab_ins);
     }
 };
+struct find_scalar_mul_add
+{
+    auto matcher() const
+    {
+        return match::name("mul")(match::either_arg(0, 1)(
+            match::name("add")(
+                match::either_arg(0, 1)(
+                    match::any().bind("x"),
+                    match::any_of(conv_const_weights(), match::is_constant()).bind("b")),
+                match::none_of(match::args(match::is_constant(), match::is_constant())),
+                match::used_once()),
+
+            match::is_scalar().bind("a")));
+    }
+
+    void apply(module& m, const match::matcher_result& r) const
+    {
+        auto ins   = r.result;
+        auto a_ins = r.instructions["a"];
+        auto b_ins = r.instructions["b"];
+        auto x_ins = r.instructions["x"];
+        assert(x_ins != b_ins);
+
+        auto xb_ins = m.insert_instruction(ins, make_op("add"), x_ins, b_ins);
+        auto result_ins = m.insert_instruction(ins, make_op("mul"), a_ins, xb_ins);
+        m.replace_instruction(ins, result_ins);
+    }
+};
 
 struct find_dot_add
 {
@@ -1595,7 +1628,8 @@ struct find_div_const
     }
 };
 
-struct find_unit_ops
+struct 
+unit_ops
 {
     auto matcher() const
     {