From eef68291aa1c8060d0e80b7e34995c2de19c4aa4 Mon Sep 17 00:00:00 2001
From: peter klausler <pklausler@nvidia.com>
Date: Tue, 8 May 2018 10:32:58 -0700
Subject: [PATCH] [flang] Build with g++ 8.1.0 compiler and headers.

Original-commit: flang-compiler/f18@53d80fc8548e04cb80b6acdd7cde1a12641657c0
Reviewed-on: https://github.com/flang-compiler/f18/pull/84
Tree-same-pre-rewrite: false
---
 flang/lib/parser/basic-parsers.h | 12 +++++++-----
 flang/lib/parser/idioms.h        |  7 ++++---
 flang/lib/parser/parse-tree.h    |  3 +--
 flang/lib/semantics/enum-set.h   |  1 -
 4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/flang/lib/parser/basic-parsers.h b/flang/lib/parser/basic-parsers.h
index 9b71421..500be4a 100644
--- a/flang/lib/parser/basic-parsers.h
+++ b/flang/lib/parser/basic-parsers.h
@@ -195,10 +195,11 @@ public:
   constexpr SequenceParser(const SequenceParser &) = default;
   constexpr SequenceParser(const PA &pa, const PB &pb) : pa_{pa}, pb_{pb} {}
   std::optional<resultType> Parse(ParseState &state) const {
+    std::optional<resultType> result;
     if (pa_.Parse(state)) {
-      return pb_.Parse(state);
+      result = pb_.Parse(state);
     }
-    return {};
+    return result;
   }
 
 private:
@@ -218,12 +219,13 @@ public:
   constexpr InvertedSequenceParser(const PA &pa, const PB &pb)
     : pa_{pa}, pb_{pb} {}
   std::optional<resultType> Parse(ParseState &state) const {
+    std::optional<resultType> result;
     if (std::optional<resultType> ax{pa_.Parse(state)}) {
       if (pb_.Parse(state)) {
-        return ax;
+        result = std::move(ax);
       }
     }
-    return {};
+    return result;
   }
 
 private:
@@ -292,7 +294,7 @@ template<typename... Ps> inline constexpr auto first(const Ps &... ps) {
 #if !__GNUC__ || __clang__
 // Implement operator|| with first(), unless compiling with g++,
 // which can segfault at compile time and needs to continue to use
-// the original implementation of operator|| as of gcc-7.3.0.
+// the original implementation of operator|| as of gcc-8.1.0.
 template<typename PA, typename PB>
 inline constexpr auto operator||(const PA &pa, const PB &pb) {
   return first(pa, pb);
diff --git a/flang/lib/parser/idioms.h b/flang/lib/parser/idioms.h
index 18a4c74f..8272c8b 100644
--- a/flang/lib/parser/idioms.h
+++ b/flang/lib/parser/idioms.h
@@ -26,7 +26,7 @@
 #error this is a C++17 program
 #endif
 #if !defined(__clang__) && defined __GNUC__ && __GNUC__ < 7
-#error G++ >= 7.0 is required
+#error g++ >= 7.3 is required
 #endif
 
 #include <list>
@@ -35,14 +35,15 @@
 #include <type_traits>
 #include <variant>
 
-// Avoid a deduction bug in GNU 7.3.0 headers by forcing the answer.
-// TODO: better resolution
+#if __GNUC__ == 7
+// Avoid a deduction bug in GNU 7.x headers by forcing the answer.
 namespace std {
 template<typename A>
 struct is_trivially_copy_constructible<list<A>> : false_type {};
 template<typename A>
 struct is_trivially_copy_constructible<optional<list<A>>> : false_type {};
 }  // namespace std
+#endif
 
 // enable "this is a std::string"s with the 's' suffix
 using namespace std::literals::string_literals;
diff --git a/flang/lib/parser/parse-tree.h b/flang/lib/parser/parse-tree.h
index 6f2dd4b..7a69d51 100644
--- a/flang/lib/parser/parse-tree.h
+++ b/flang/lib/parser/parse-tree.h
@@ -47,7 +47,7 @@
 // Parse tree node class types do not have copy constructors or copy assignment
 // operators.  They are explicitly declared "= delete;" to make this clear,
 // although a C++ compiler wouldn't default them anyway due to the presence
-// of move constructors and move assignments.
+// of explicitly defaulted move constructors and move assignments.
 
 CLASS_TRAIT(EmptyTrait);
 CLASS_TRAIT(WrapperTrait);
@@ -710,7 +710,6 @@ struct SignedIntLiteralConstant {
 // R708 int-literal-constant -> digit-string [_ kind-param]
 struct IntLiteralConstant {
   TUPLE_CLASS_BOILERPLATE(IntLiteralConstant);
-  IntLiteralConstant(std::uint64_t n) : t{n, std::optional<KindParam>{}} {}
   std::tuple<std::uint64_t, std::optional<KindParam>> t;
 };
 
diff --git a/flang/lib/semantics/enum-set.h b/flang/lib/semantics/enum-set.h
index 017314e..33ad380 100644
--- a/flang/lib/semantics/enum-set.h
+++ b/flang/lib/semantics/enum-set.h
@@ -20,7 +20,6 @@
 
 #include <bitset>
 #include <cstddef>
-#include <functional>
 
 namespace Fortran::semantics {
 
-- 
2.7.4