Remove code pieces for no longer supported GCC versions.

The minimum supported version today is GCC 7 (`__GNUC__ >= 7`).

PiperOrigin-RevId: 600475215
Change-Id: I1aa46384f1e75f268649a48dbe2b42f3475bb07f

absl/base/config.h

@@ -379,9 +379,7 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #define ABSL_HAVE_EXCEPTIONS 1
 #endif  // defined(__EXCEPTIONS) && ABSL_HAVE_FEATURE(cxx_exceptions)
 // Handle remaining special cases and default to exceptions being supported.
-#elif !(defined(__GNUC__) && (__GNUC__ < 5) && !defined(__EXCEPTIONS)) && \
-    !(ABSL_INTERNAL_HAVE_MIN_GNUC_VERSION(5, 0) &&                        \
-      !defined(__cpp_exceptions)) &&                                      \
+#elif !(defined(__GNUC__) && !defined(__cpp_exceptions)) && \
     !(defined(_MSC_VER) && !defined(_CPPUNWIND))
 #define ABSL_HAVE_EXCEPTIONS 1
 #endif
@@ -902,9 +900,7 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #error ABSL_INTERNAL_HAS_CXA_DEMANGLE cannot be directly set
 #elif defined(OS_ANDROID) && (defined(__i386__) || defined(__x86_64__))
 #define ABSL_INTERNAL_HAS_CXA_DEMANGLE 0
-#elif defined(__GNUC__) && defined(__GNUC_MINOR__) &&            \
-    (__GNUC__ >= 4 || (__GNUC__ >= 3 && __GNUC_MINOR__ >= 4)) && \
-    !defined(__mips__)
+#elif defined(__GNUC__) && !defined(__mips__)
 #define ABSL_INTERNAL_HAS_CXA_DEMANGLE 1
 #elif defined(__clang__) && !defined(_MSC_VER)
 #define ABSL_INTERNAL_HAS_CXA_DEMANGLE 1

absl/container/internal/compressed_tuple_test.cc

@@ -358,7 +358,6 @@ TEST(CompressedTupleTest, Constexpr) {
   EXPECT_EQ(x2, 5);
   EXPECT_EQ(x3, CallType::kConstRef);
 
-#if !defined(__GNUC__) || defined(__clang__) || __GNUC__ > 4
   constexpr CompressedTuple<Empty<0>, TrivialStruct, int> trivial = {};
   constexpr CallType trivial0 = trivial.get<0>().value();
   constexpr int trivial1 = trivial.get<1>().value();
@@ -367,7 +366,6 @@ TEST(CompressedTupleTest, Constexpr) {
   EXPECT_EQ(trivial0, CallType::kConstRef);
   EXPECT_EQ(trivial1, 0);
   EXPECT_EQ(trivial2, 0);
-#endif
 
   constexpr CompressedTuple<Empty<0>, NonTrivialStruct, absl::optional<int>>
       non_trivial = {};

absl/container/internal/hash_policy_testing.h

@@ -174,8 +174,7 @@ ABSL_NAMESPACE_END
 // From GCC-4.9 Changelog: (src: https://gcc.gnu.org/gcc-4.9/changes.html)
 // "the unordered associative containers in <unordered_map> and <unordered_set>
 // meet the allocator-aware container requirements;"
-#if (defined(__GLIBCXX__) && __GLIBCXX__ <= 20140425 ) || \
-( __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 9 ))
+#if defined(__GLIBCXX__) && __GLIBCXX__ <= 20140425
 #define ABSL_UNORDERED_SUPPORTS_ALLOC_CTORS 0
 #else
 #define ABSL_UNORDERED_SUPPORTS_ALLOC_CTORS 1

absl/flags/flag_test.cc

@@ -1044,13 +1044,7 @@ TEST_F(FlagTest, MacroWithinAbslFlag) {
 
 // --------------------------------------------------------------------
 
-#if defined(__GNUC__) && !defined(__clang__) && __GNUC__ <= 5
-#define ABSL_SKIP_OPTIONAL_BOOL_TEST_DUE_TO_GCC_BUG
-#endif
-
-#ifndef ABSL_SKIP_OPTIONAL_BOOL_TEST_DUE_TO_GCC_BUG
 ABSL_FLAG(absl::optional<bool>, optional_bool, absl::nullopt, "help");
-#endif
 ABSL_FLAG(absl::optional<int>, optional_int, {}, "help");
 ABSL_FLAG(absl::optional<double>, optional_double, 9.3, "help");
 ABSL_FLAG(absl::optional<std::string>, optional_string, absl::nullopt, "help");
@@ -1064,7 +1058,6 @@ ABSL_FLAG(std::optional<int64_t>, std_optional_int64, std::nullopt, "help");
 
 namespace {
 
-#ifndef ABSL_SKIP_OPTIONAL_BOOL_TEST_DUE_TO_GCC_BUG
 TEST_F(FlagTest, TestOptionalBool) {
   EXPECT_FALSE(absl::GetFlag(FLAGS_optional_bool).has_value());
   EXPECT_EQ(absl::GetFlag(FLAGS_optional_bool), absl::nullopt);
@@ -1083,7 +1076,6 @@ TEST_F(FlagTest, TestOptionalBool) {
 }
 
 // --------------------------------------------------------------------
-#endif
 
 TEST_F(FlagTest, TestOptionalInt) {
   EXPECT_FALSE(absl::GetFlag(FLAGS_optional_int).has_value());

absl/types/optional_test.cc

@@ -982,18 +982,6 @@ TEST(optionalTest, PointerStuff) {
   static_assert((*opt1).x == ConstexprType::kCtorInt, "");
 }
 
-// gcc has a bug pre 4.9.1 where it doesn't do correct overload resolution
-// when overloads are const-qualified and *this is an raluve.
-// Skip that test to make the build green again when using the old compiler.
-// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59296 is fixed in 4.9.1.
-#if defined(__GNUC__) && !defined(__clang__)
-#define GCC_VERSION \
-  (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__)
-#if GCC_VERSION < 40901
-#define ABSL_SKIP_OVERLOAD_TEST_DUE_TO_GCC_BUG
-#endif
-#endif
-
 TEST(optionalTest, Value) {
   using O = absl::optional<std::string>;
   using CO = const absl::optional<std::string>;
@@ -1006,16 +994,12 @@ TEST(optionalTest, Value) {
   EXPECT_EQ("lvalue_c", lvalue_c.value());
   EXPECT_EQ("xvalue", O(absl::in_place, "xvalue").value());
   EXPECT_EQ("xvalue_c", OC(absl::in_place, "xvalue_c").value());
-#ifndef ABSL_SKIP_OVERLOAD_TEST_DUE_TO_GCC_BUG
   EXPECT_EQ("cxvalue", CO(absl::in_place, "cxvalue").value());
-#endif
   EXPECT_EQ("&", TypeQuals(lvalue.value()));
   EXPECT_EQ("c&", TypeQuals(clvalue.value()));
   EXPECT_EQ("c&", TypeQuals(lvalue_c.value()));
   EXPECT_EQ("&&", TypeQuals(O(absl::in_place, "xvalue").value()));
-#ifndef ABSL_SKIP_OVERLOAD_TEST_DUE_TO_GCC_BUG
   EXPECT_EQ("c&&", TypeQuals(CO(absl::in_place, "cxvalue").value()));
-#endif
   EXPECT_EQ("c&&", TypeQuals(OC(absl::in_place, "xvalue_c").value()));
 
 #if !defined(ABSL_VOLATILE_RETURN_TYPES_DEPRECATED)
@@ -1039,7 +1023,7 @@ TEST(optionalTest, Value) {
   // test constexpr value()
   constexpr absl::optional<int> o1(1);
   static_assert(1 == o1.value(), "");  // const &
-#if !defined(_MSC_VER) && !defined(ABSL_SKIP_OVERLOAD_TEST_DUE_TO_GCC_BUG)
+#ifndef _MSC_VER
   using COI = const absl::optional<int>;
   static_assert(2 == COI(2).value(), "");  // const &&
 #endif
@@ -1057,15 +1041,11 @@ TEST(optionalTest, DerefOperator) {
   EXPECT_EQ("lvalue_c", *lvalue_c);
   EXPECT_EQ("xvalue", *O(absl::in_place, "xvalue"));
   EXPECT_EQ("xvalue_c", *OC(absl::in_place, "xvalue_c"));
-#ifndef ABSL_SKIP_OVERLOAD_TEST_DUE_TO_GCC_BUG
   EXPECT_EQ("cxvalue", *CO(absl::in_place, "cxvalue"));
-#endif
   EXPECT_EQ("&", TypeQuals(*lvalue));
   EXPECT_EQ("c&", TypeQuals(*clvalue));
   EXPECT_EQ("&&", TypeQuals(*O(absl::in_place, "xvalue")));
-#ifndef ABSL_SKIP_OVERLOAD_TEST_DUE_TO_GCC_BUG
   EXPECT_EQ("c&&", TypeQuals(*CO(absl::in_place, "cxvalue")));
-#endif
   EXPECT_EQ("c&&", TypeQuals(*OC(absl::in_place, "xvalue_c")));
 
 #if !defined(ABSL_VOLATILE_RETURN_TYPES_DEPRECATED)