Implement P2614R2 Deprecating `float_denorm_style`, `numeric_limits::has_denorm`, `numeric_limits::has_denorm_loss` (#3482)

stl/inc/limits

@@ -36,7 +36,8 @@ _STL_DISABLE_CLANG_WARNINGS
 #undef new
 
 _STD_BEGIN
-_EXPORT_STD enum float_denorm_style { // constants for different IEEE float denormalization styles
+// constants for different IEEE float denormalization styles
+_EXPORT_STD enum _CXX23_DEPRECATE_DENORM float_denorm_style {
     denorm_indeterminate = -1,
     denorm_absent        = 0,
     denorm_present       = 1
@@ -51,8 +52,11 @@ _EXPORT_STD enum float_round_style { // constants for different IEEE rounding st
 };
 
 struct _Num_base { // base for all types, with common defaults
-    static constexpr float_denorm_style has_denorm = denorm_absent;
-    static constexpr bool has_denorm_loss          = false;
+    _STL_DISABLE_DEPRECATED_WARNING
+    _CXX23_DEPRECATE_DENORM static constexpr float_denorm_style has_denorm = denorm_absent;
+    _CXX23_DEPRECATE_DENORM static constexpr bool has_denorm_loss          = false;
+    _STL_RESTORE_DEPRECATED_WARNING
+
     static constexpr bool has_infinity             = false;
     static constexpr bool has_quiet_NaN            = false;
     static constexpr bool has_signaling_NaN        = false;
@@ -134,7 +138,10 @@ struct _Num_int_base : _Num_base { // base for integer types
 };
 
 struct _Num_float_base : _Num_base { // base for floating-point types
-    static constexpr float_denorm_style has_denorm = denorm_present;
+    _STL_DISABLE_DEPRECATED_WARNING
+    _CXX23_DEPRECATE_DENORM static constexpr float_denorm_style has_denorm = denorm_present;
+    _STL_RESTORE_DEPRECATED_WARNING
+
     static constexpr bool has_infinity             = true;
     static constexpr bool has_quiet_NaN            = true;
     static constexpr bool has_signaling_NaN        = true;

stl/inc/yvals_core.h

@@ -365,6 +365,7 @@
 
 // _HAS_CXX23 and _SILENCE_ALL_CXX23_DEPRECATION_WARNINGS control:
 // P1413R3 Deprecate aligned_storage And aligned_union
+// P2614R2 Deprecating float_denorm_style, numeric_limits::has_denorm, numeric_limits::has_denorm_loss
 // Other C++23 deprecation warnings
 
 // Parallel Algorithms Notes
@@ -1431,7 +1432,18 @@ _EMIT_STL_ERROR(STL1004, "C++98 unexpected() is incompatible with C++23 unexpect
 #define _CXX23_DEPRECATE_UNIX_STREAMS
 #endif // ^^^ warning disabled ^^^
 
-// next warning number: STL4042
+#if _HAS_CXX23 && !defined(_SILENCE_CXX23_DENORM_DEPRECATION_WARNING) \
+    && !defined(_SILENCE_ALL_CXX23_DEPRECATION_WARNINGS)
+#define _CXX23_DEPRECATE_DENORM                                                                                        \
+    [[deprecated("warning STL4042: "                                                                                   \
+                 "std::float_denorm_style, std::numeric_limits::has_denorm, and std::numeric_limits::has_denorm_loss " \
+                 "are deprecated in C++23. You can define _SILENCE_CXX23_DENORM_DEPRECATION_WARNING or "               \
+                 "_SILENCE_ALL_CXX23_DEPRECATION_WARNINGS to suppress this warning.")]]
+#else // ^^^ warning enabled / warning disabled vvv
+#define _CXX23_DEPRECATE_DENORM
+#endif // ^^^ warning disabled ^^^
+
+// next warning number: STL4043
 
 // next error number: STL1006
 

tests/std/tests/Dev11_1074023_constexpr/test.cpp

@@ -6,6 +6,7 @@
 #define _SILENCE_CXX17_IS_LITERAL_TYPE_DEPRECATION_WARNING
 #define _SILENCE_CXX17_NEGATORS_DEPRECATION_WARNING
 #define _SILENCE_CXX20_IS_POD_DEPRECATION_WARNING
+#define _SILENCE_CXX23_DENORM_DEPRECATION_WARNING
 
 #include <algorithm>
 #include <array>

tests/tr1/tests/limits/test.cpp

@@ -4,6 +4,8 @@
 // test <limits>
 #define TEST_NAME "<limits>"
 
+#define _SILENCE_CXX23_DENORM_DEPRECATION_WARNING
+
 #include "tdefs.h"
 #include <float.h>
 #include <limits.h>