Remove preprocessors for now unsupported compilers.

PiperOrigin-RevId: 719126950
Change-Id: I0978c295896acdf069175ba99156e8bbf6e1e188

absl/functional/bind_front_test.cc

diff --git a/absl/functional/bind_front_test.cc b/absl/functional/bind_front_test.cc
index 4801a81..5d94ecc 100644
--- a/absl/functional/bind_front_test.cc
+++ b/absl/functional/bind_front_test.cc
@@ -210,13 +210,9 @@
   constexpr auto plus5 = absl::bind_front(Plus, five);
   EXPECT_EQ(plus5(1), 6);
 
-  // There seems to be a bug in MSVC dealing constexpr construction of
-  // char[]. Notice 'plus5' above; 'int' works just fine.
-#if !(defined(_MSC_VER) && _MSC_VER < 1910)
   static constexpr char data[] = "DEF";
   constexpr auto g = absl::bind_front(CharAt, data);
   EXPECT_EQ(g(1), 'E');
-#endif
 }
 
 struct ManglingCall {

absl/strings/charconv.cc

diff --git a/absl/strings/charconv.cc b/absl/strings/charconv.cc
index 0c9227f..66c12cc 100644
--- a/absl/strings/charconv.cc
+++ b/absl/strings/charconv.cc
@@ -359,16 +359,13 @@
 bool HandleEdgeCase(const strings_internal::ParsedFloat& input, bool negative,
                     absl::Nonnull<FloatType*> value) {
   if (input.type == strings_internal::FloatType::kNan) {
-    // A bug in both clang < 7 and gcc would cause the compiler to optimize
-    // away the buffer we are building below.  Declaring the buffer volatile
-    // avoids the issue, and has no measurable performance impact in
-    // microbenchmarks.
+    // A bug in gcc would cause the compiler to optimize away the buffer we are
+    // building below.  Declaring the buffer volatile avoids the issue, and has
+    // no measurable performance impact in microbenchmarks.
     //
-    // https://bugs.llvm.org/show_bug.cgi?id=37778
     // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86113
     constexpr ptrdiff_t kNanBufferSize = 128;
-#if (defined(__GNUC__) && !defined(__clang__)) || \
-    (defined(__clang__) && __clang_major__ < 7)
+#if (defined(__GNUC__) && !defined(__clang__))
     volatile char n_char_sequence[kNanBufferSize];
 #else
     char n_char_sequence[kNanBufferSize];

absl/strings/string_view_test.cc

diff --git a/absl/strings/string_view_test.cc b/absl/strings/string_view_test.cc
index e810b25..7064cc7 100644
--- a/absl/strings/string_view_test.cc
+++ b/absl/strings/string_view_test.cc
@@ -1123,7 +1123,7 @@
 #endif
 
 // MSVC 2017+ should be able to construct a constexpr string_view from a cstr.
-#if defined(_MSC_VER) && _MSC_VER >= 1910
+#if defined(_MSC_VER)
 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
 #endif
 
@@ -1159,10 +1159,6 @@
 #endif
 #endif
 
-#if !defined(__clang__) || 3 < __clang_major__ || \
-  (3 == __clang_major__ && 4 < __clang_minor__)
-  // older clang versions (< 3.5) complain that:
-  //   "cannot perform pointer arithmetic on null pointer"
   constexpr absl::string_view::iterator const_begin_empty = sp.begin();
   constexpr absl::string_view::iterator const_end_empty = sp.end();
   EXPECT_EQ(const_begin_empty, const_end_empty);
@@ -1172,7 +1168,6 @@
   constexpr absl::string_view::iterator const_end_nullptr = cstr.end();
   EXPECT_EQ(const_begin_nullptr, const_end_nullptr);
 #endif  // ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
-#endif  // !defined(__clang__) || ...
 
   constexpr absl::string_view::iterator const_begin = cstr_len.begin();
   constexpr absl::string_view::iterator const_end = cstr_len.end();