Add use of implicit deps inside sorting function (#2005)

* use implicit deps for the sorting
* use BFS for sorting program

src/include/migraphx/module.hpp

@@ -222,7 +222,17 @@ struct MIGRAPHX_EXPORT module
     void annotate(std::ostream& os, std::function<void(instruction_ref)> a) const;
 
     std::vector<module_ref> get_sub_modules(bool shallow = false) const;
+    /* sorts the module in topological order aka reverse-post order (RPO) DFS order
+       it takes last instruction or @return as the root and walks back the graph and moves inputs
+       of the each instruction such that it appears before the instruction itself.
+    */
     module& sort();
+    /* Any instruction "X" can have module arguments and those modules inside them can use any other
+     * instruction "Y" from predecessor modules of the instruction "X". Such instruction "Y" inside
+     * module args are not listed as input instructions to "X". But those instructions "Y" must be
+     * evaluted before the instruction "X" can. Therefore such "Y" instructions are considered
+     * implicit dependency to "X".
+     */
     ins_dep_map calc_implicit_deps() const;
 
     MIGRAPHX_EXPORT friend std::ostream& operator<<(std::ostream& os, const module& m);

src/module.cpp

@@ -1011,9 +1011,17 @@ std::vector<module_ref> module::get_sub_modules(bool shallow) const
 
 module& module::sort()
 {
+    auto implicit_deps = calc_implicit_deps();
     fix([&](auto self, auto ins) {
         this->move_instruction(ins, this->begin());
-        for(auto child : ins->inputs())
+        auto ins_inputs = ins->inputs();
+        if(implicit_deps.find(ins) != implicit_deps.end())
+        {
+            auto ins_implict_inputs = implicit_deps.at(ins);
+            ins_inputs.insert(
+                ins_inputs.end(), ins_implict_inputs.begin(), ins_implict_inputs.end());
+        }
+        for(auto child : ins_inputs)
         {
             if(not contains(this->impl->instructions, child))
             {

src/program.cpp

@@ -40,13 +40,14 @@
 #include <migraphx/make_op.hpp>
 #include <migraphx/marker.hpp>
 #include <migraphx/supported_segments.hpp>
+
 #include <iostream>
+#include <queue>
 #include <sstream>
 #include <algorithm>
 #include <set>
 #include <unordered_map>
 #include <utility>
-
 #include <unordered_set>
 #include <map>
 #include <cassert>
@@ -1191,11 +1192,19 @@ void program::remove_unused_modules()
 
 program& program::sort()
 {
-    for(auto& pp : this->impl->modules)
+    std::queue<migraphx::module_ref> mqueue;
+    mqueue.push(get_main_module());
+    while(not mqueue.empty())
     {
-        pp.second.sort();
+        module_ref current_mod = mqueue.front();
+        current_mod->sort();
+        mqueue.pop();
+        auto child_mods = current_mod->get_sub_modules(true);
+        for(auto& sub_mod : child_mods)
+        {
+            mqueue.push(sub_mod);
+        }
     }
-
     return *this;
 }
 

test/module_test.cpp

@@ -83,7 +83,7 @@ TEST_CASE(calc_implict_deps)
     auto* else_mod = p.create_module("If_5_else");
     auto l2        = else_mod->add_literal(migraphx::literal(ys, datay));
     auto a2 = else_mod->add_instruction(migraphx::make_op("if"), {cond}, {then_mod1, else_mod1});
-    auto a3 = mm->add_instruction(migraphx::make_op("get_tuple_elem", {{"index", 0}}), a2);
+    auto a3 = else_mod->add_instruction(migraphx::make_op("get_tuple_elem", {{"index", 0}}), a2);
     else_mod->add_return({a3, l2});
 
     auto ret = mm->add_instruction(migraphx::make_op("if"), {cond}, {then_mod, else_mod});
@@ -95,6 +95,15 @@ TEST_CASE(calc_implict_deps)
     EXPECT(migraphx::contains(implicit_deps.at(ret), x1));
     EXPECT(migraphx::contains(implicit_deps.at(ret), x2));
     EXPECT(migraphx::contains(implicit_deps.at(ret), y2));
+    EXPECT(migraphx::contains(implicit_deps.at(ret), lx));
+    EXPECT(migraphx::contains(implicit_deps.at(ret), ly));
+    // test for sorting
+    p.sort();
+    auto ret_inputs = ret->inputs();
+    ret_inputs.insert(ret_inputs.end(), implicit_deps.at(ret).begin(), implicit_deps.at(ret).end());
+    EXPECT(std::all_of(ret_inputs.begin(), ret_inputs.end(), [&](const auto i) {
+        return std::distance(mm->begin(), i) < std::distance(mm->begin(), ret);
+    }));
 }
 
 TEST_CASE(module_annotate)