[clang] [C23] Add *_NORM_MAX macros to <float.h> (PR #96643)
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Tue Jun 25 07:30:10 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-x86
Author: Aaron Ballman (AaronBallman)
<details>
<summary>Changes</summary>
This adds the *_NORM_MAX macros to <float.h> for freestanding mode in Clang; the values were chosen based on the behavior seen coming from GCC and the values already produced for the *_MAX macros by Clang.
---
Full diff: https://github.com/llvm/llvm-project/pull/96643.diff
4 Files Affected:
- (modified) clang/docs/ReleaseNotes.rst (+3)
- (modified) clang/lib/Frontend/InitPreprocessor.cpp (+6-1)
- (modified) clang/lib/Headers/float.h (+13)
- (modified) clang/test/Headers/float.c (+27)
``````````diff
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index df579ae398c5e..8879a77ba4dd9 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -336,6 +336,9 @@ C23 Feature Support
- Properly promote bit-fields of bit-precise integer types to the field's type
rather than to ``int``. #GH87641
+- Added the ``FLT_NORM_MAX``, ``DBL_NORM_MAX``, and ``LDBL_NORM_MAX`` to the
+ freestanding implementation of ``<float.h>`` that ships with Clang.
+
Non-comprehensive list of changes in this release
-------------------------------------------------
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 55ec460064830..afc4c16ab685b 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -113,7 +113,11 @@ static T PickFP(const llvm::fltSemantics *Sem, T IEEEHalfVal, T IEEESingleVal,
static void DefineFloatMacros(MacroBuilder &Builder, StringRef Prefix,
const llvm::fltSemantics *Sem, StringRef Ext) {
- const char *DenormMin, *Epsilon, *Max, *Min;
+ const char *DenormMin, *NormMax, *Epsilon, *Max, *Min;
+ NormMax = PickFP(Sem, "6.5504e+4", "3.40282347e+38",
+ "1.7976931348623157e+308", "1.18973149535723176502e+4932",
+ "1.79769313486231580793728971405301e+308",
+ "1.18973149535723176508575932662800702e+4932");
DenormMin = PickFP(Sem, "5.9604644775390625e-8", "1.40129846e-45",
"4.9406564584124654e-324", "3.64519953188247460253e-4951",
"4.94065645841246544176568792868221e-324",
@@ -144,6 +148,7 @@ static void DefineFloatMacros(MacroBuilder &Builder, StringRef Prefix,
DefPrefix += "_";
Builder.defineMacro(DefPrefix + "DENORM_MIN__", Twine(DenormMin)+Ext);
+ Builder.defineMacro(DefPrefix + "NORM_MAX__", Twine(NormMax)+Ext);
Builder.defineMacro(DefPrefix + "HAS_DENORM__");
Builder.defineMacro(DefPrefix + "DIG__", Twine(Digits));
Builder.defineMacro(DefPrefix + "DECIMAL_DIG__", Twine(DecimalDigits));
diff --git a/clang/lib/Headers/float.h b/clang/lib/Headers/float.h
index 642c8f06cc938..61f65dad8debc 100644
--- a/clang/lib/Headers/float.h
+++ b/clang/lib/Headers/float.h
@@ -86,6 +86,12 @@
# undef DBL_HAS_SUBNORM
# undef LDBL_HAS_SUBNORM
# endif
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || \
+ !defined(__STRICT_ANSI__)
+# undef FLT_NORM_MAX
+# undef DBL_NORM_MAX
+# undef LDBL_NORM_MAX
+#endif
#endif
/* Characteristics of floating point types, C99 5.2.4.2.2 */
@@ -155,6 +161,13 @@
# define LDBL_HAS_SUBNORM __LDBL_HAS_DENORM__
#endif
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || \
+ !defined(__STRICT_ANSI__)
+# define FLT_NORM_MAX __FLT_NORM_MAX__
+# define DBL_NORM_MAX __DBL_NORM_MAX__
+# define LDBL_NORM_MAX __LDBL_NORM_MAX__
+#endif
+
#ifdef __STDC_WANT_IEC_60559_TYPES_EXT__
# define FLT16_MANT_DIG __FLT16_MANT_DIG__
# define FLT16_DECIMAL_DIG __FLT16_DECIMAL_DIG__
diff --git a/clang/test/Headers/float.c b/clang/test/Headers/float.c
index 70c11b0537537..59cc0faa074db 100644
--- a/clang/test/Headers/float.c
+++ b/clang/test/Headers/float.c
@@ -1,17 +1,21 @@
// RUN: %clang_cc1 -fsyntax-only -verify -std=c89 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c99 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -std=c11 -ffreestanding %s
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c23 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -xc++ -std=c++11 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -xc++ -std=c++14 -ffreestanding %s
// RUN: %clang_cc1 -fsyntax-only -verify -xc++ -std=c++17 -ffreestanding %s
+// RUN: %clang_cc1 -fsyntax-only -verify -xc++ -std=c++23 -ffreestanding %s
// expected-no-diagnostics
/* Basic floating point conformance checks against:
+ - C23 Final Std.
- N1570 draft of C11 Std.
- N1256 draft of C99 Std.
- http://port70.net/~nsz/c/c89/c89-draft.html draft of C89/C90 Std.
*/
/*
+ C23, 5.2.5.3.3p21, pp. 25
C11, 5.2.4.2.2p11, pp. 30
C99, 5.2.4.2.2p9, pp. 25
C89, 2.2.4.2
@@ -207,6 +211,23 @@
#error "Mandatory macros {FLT,DBL,LDBL}_MAX_10_EXP are invalid."
#endif
+#if __STDC_VERSION__ >= 202311L || !defined(__STRICT_ANSI__)
+#ifndef FLT_NORM_MAX
+ #error "Mandatory macro FLT_NORM_MAX is missing."
+#else
+ _Static_assert(FLT_NORM_MAX >= 1.0E+37F, "Mandatory macro FLT_NORM_MAX is invalid.");
+#endif
+#ifndef DBL_NORM_MAX
+ #error "Mandatory macro DBL_NORM_MAX is missing."
+#else
+ _Static_assert(DBL_NORM_MAX >= 1.0E+37F, "Mandatory macro DBL_NORM_MAX is invalid.");
+#endif
+#ifndef LDBL_NORM_MAX
+ #error "Mandatory macro LDBL_NORM_MAX is missing."
+#else
+ _Static_assert(LDBL_NORM_MAX >= 1.0E+37F, "Mandatory macro LDBL_NORM_MAX is invalid.");
+#endif
+#endif
/* Internal consistency checks */
_Static_assert(FLT_RADIX == __FLT_RADIX__, "");
@@ -244,3 +265,9 @@ _Static_assert(LDBL_MAX_EXP == __LDBL_MAX_EXP__, "");
_Static_assert(FLT_MAX_10_EXP == __FLT_MAX_10_EXP__, "");
_Static_assert(DBL_MAX_10_EXP == __DBL_MAX_10_EXP__, "");
_Static_assert(LDBL_MAX_10_EXP == __LDBL_MAX_10_EXP__, "");
+
+#if __STDC_VERSION__ >= 202311L || !defined(__STRICT_ANSI__)
+_Static_assert(FLT_NORM_MAX == __FLT_NORM_MAX__, "");
+_Static_assert(DBL_NORM_MAX == __DBL_NORM_MAX__, "");
+_Static_assert(LDBL_NORM_MAX == __LDBL_NORM_MAX__, "");
+#endif
``````````
</details>
https://github.com/llvm/llvm-project/pull/96643
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