Try to fix ice on gcc 5

src/include/migraphx/functional.hpp

@@ -190,10 +190,21 @@ auto pop_back_args(Ts&&... xs)
     };
 }
 
+template<class T>
+struct always_f
+{
+    T x;
+    template<class... Ts>
+    constexpr T operator()(Ts&&...) const
+    {
+        return x;
+    }
+};
+
 template <class T>
 auto always(T x)
 {
-    return [=](auto&&...) { return x; };
+    return always_f<T>{x};
 }
 
 } // namespace MIGRAPHX_INLINE_NS

src/include/migraphx/matcher.hpp

@@ -261,14 +261,21 @@ struct lazy_or
 template <class Op, bool Start, bool Matches>
 struct folder
 {
-    template <class... Ts>
-    auto operator()(Ts... ms) const
+    template<class... Ms>
+    static bool fold_match(matcher_context& ctx, instruction_ref ins, Ms... ms)
     {
-        return make_bf_matcher([=](matcher_context& ctx, instruction_ref ins) {
         Op op;
         auto matched = [&](auto m) { return [&] { return ctx.matched(m, ins); }; };
-            bool matches =
+        return
             fold([&](auto x, auto y) { return op(always(x), matched(y)); })(Start, ms...);
+    }
+
+
+    template <class... Ts>
+    auto operator()(Ts... ms) const
+    {
+        return make_bf_matcher([=](matcher_context& ctx, instruction_ref ins) {
+            bool matches = folder::fold_match(ctx, ins, ms...);
             if(matches == Matches)
                 return ins;
             return ctx.not_found();
@@ -283,12 +290,8 @@ struct folder
                 Op op;
                 bool matches = Start;
                 select(start, [&](auto ins) {
-                    auto matched    = [&](auto m) { return [&] { return ctx.matched(m, ins); }; };
-                    auto fold_match = [&] {
-                        return fold([&](auto x, auto y) { return op(always(x), matched(y)); })(
-                            Start, ms...);
-                    };
-                    matches = op(always(matches), fold_match);
+                    auto fm = [&] { return folder::fold_match(ctx, ins, ms...); };
+                    matches = op(always(matches), fm);
                 });
                 if(matches == Matches)
                     return start;

test/matcher.cpp

@@ -148,6 +148,20 @@ TEST_CASE(match_arg7)
     EXPECT(bool{r.result == sum});
 }
 
+TEST_CASE(match_arg8)
+{
+    migraphx::program p;
+    auto one = p.add_literal(1);
+    auto two = p.add_literal(2);
+    auto sum = p.add_instruction(sum_op{}, one, two);
+    p.add_instruction(pass_op{}, sum);
+    auto m = match::name("sum")(match::all_of(match::arg(0)(match::name("@literal")),
+                                match::arg(1)(match::name("@literal"))),
+                                match::standard_shape());
+    auto r = find_match(p, m);
+    EXPECT(bool{r.result == sum});
+}
+
 TEST_CASE(match_args1)
 {
     migraphx::program p;