[clang] [C23] Add INFINITY and NAN macros to <float.h> (PR #96659)
Aaron Ballman via cfe-commits
cfe-commits at lists.llvm.org
Mon Jul 1 05:58:49 PDT 2024
https://github.com/AaronBallman updated https://github.com/llvm/llvm-project/pull/96659
>From b59c7f8c91d7c128975554d90bef3657ce3b2728 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Tue, 25 Jun 2024 10:52:56 -0400
Subject: [PATCH 1/4] [C23] Add INFINITY and NAN macros to <float.h>
This is in support of WG14 N2848 which only define the macros if
infinity and nan are supported, so use of -ffinite-math will cause the
macros to not be defined.
---
clang/docs/ReleaseNotes.rst | 5 +++++
clang/lib/Headers/float.h | 6 ++++++
clang/test/Headers/float.c | 29 +++++++++++++++++++++++++++++
3 files changed, 40 insertions(+)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index df579ae398c5e..45c9a2cc47b09 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -336,6 +336,11 @@ C23 Feature Support
- Properly promote bit-fields of bit-precise integer types to the field's type
rather than to ``int``. #GH87641
+- Added the ``INFINITY`` and ``NAN`` macros to Clang's ``<float.h>``
+ freestanding implementation; these macros were defined in C99 but Clang
+ implements the macros as described by C23 in
+ `WG14 N2848 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2848.pdf>`_.
+
Non-comprehensive list of changes in this release
-------------------------------------------------
diff --git a/clang/lib/Headers/float.h b/clang/lib/Headers/float.h
index 642c8f06cc938..929c0854a865b 100644
--- a/clang/lib/Headers/float.h
+++ b/clang/lib/Headers/float.h
@@ -47,6 +47,8 @@
(defined(__cplusplus) && __cplusplus >= 201103L) || \
(__STDC_HOSTED__ && defined(_AIX) && defined(_ALL_SOURCE))
# undef DECIMAL_DIG
+# undef INFINITY
+# undef NAN
# endif
# undef FLT_DIG
# undef DBL_DIG
@@ -93,6 +95,10 @@
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
(defined(__cplusplus) && __cplusplus >= 201103L)
#define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
+#if defined(__FINITE_MATH_ONLY__) && !__FINITE_MATH_ONLY__
+# define INFINITY (__builtin_infinity())
+# define NAN (__builtin_nan(""))
+#endif
#endif
#define FLT_ROUNDS (__builtin_flt_rounds())
#define FLT_RADIX __FLT_RADIX__
diff --git a/clang/test/Headers/float.c b/clang/test/Headers/float.c
index 70c11b0537537..8dfbc32521ade 100644
--- a/clang/test/Headers/float.c
+++ b/clang/test/Headers/float.c
@@ -1,9 +1,13 @@
// 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 -std=c23 -ffreestanding -ffinite-math-only %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
+// RUN: %clang_cc1 -fsyntax-only -verify -xc++ -std=c++23 -ffreestanding -ffinite-math-only %s
// expected-no-diagnostics
/* Basic floating point conformance checks against:
@@ -107,10 +111,35 @@
#elif DECIMAL_DIG < 10
#error "Mandatory macro DECIMAL_DIG is invalid."
#endif
+
+ #if __FINITE_MATH_ONLY__ == 0
+ #ifndef INFINITY
+ #error "Mandatory macro INFINITY is missing."
+ #endif
+ #ifndef NAN
+ #error "Mandatory macro NAN is missing."
+ #endif
+ #else
+ #ifdef INFINITY
+ #error "Macro INFINITY should not be defined."
+ #endif
+
+ #ifdef NAN
+ #error "Macro NAN should not be defined."
+ #endif
+ #endif
#else
#ifdef DECIMAL_DIG
#error "Macro DECIMAL_DIG should not be defined."
#endif
+
+ #ifdef INFINITY
+ #error "Macro INFINITY should not be defined."
+ #endif
+
+ #ifdef NAN
+ #error "Macro NAN should not be defined."
+ #endif
#endif
>From 86055e3ecb25befdffdf17f2a1eb8b9c704a1e7a Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Tue, 25 Jun 2024 10:55:03 -0400
Subject: [PATCH 2/4] Update the status page
---
clang/www/c_status.html | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/clang/www/c_status.html b/clang/www/c_status.html
index 04c1df9ebc050..bc37f8cd5e404 100644
--- a/clang/www/c_status.html
+++ b/clang/www/c_status.html
@@ -991,7 +991,7 @@ <h2 id="c2x">C23 implementation status</h2>
<tr>
<td>Contradiction about INFINITY macro</td>
<td><a href="https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2848.pdf">N2848</a></td>
- <td class="unknown" align="center">Unknown</td>
+ <td class="unreleased" align="center">Clang 19</td>
</tr>
<tr>
<td>Require exact-width integer type interfaces</td>
>From 88019c9964068a43f96f1ab13b75fb6e60238470 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Fri, 28 Jun 2024 08:31:45 -0400
Subject: [PATCH 3/4] Update based on review feedback
* Now defines the macros even in -ffinite-math-only mode
* Defines the macros only in C23 and up, not in C99 and up
* Fixed the test coverage, added tests for use in a constant expression
* Fixed the expansion of the INFINITY macro (should resolve a precommit CI issue)
---
clang/docs/ReleaseNotes.rst | 4 ++--
clang/lib/Headers/float.h | 11 +++++----
clang/test/Headers/float.c | 46 +++++++++++++++++--------------------
3 files changed, 30 insertions(+), 31 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 8fcd175a3f123..9c7268cbe25b6 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -338,8 +338,8 @@ C23 Feature Support
rather than to ``int``. #GH87641
- Added the ``INFINITY`` and ``NAN`` macros to Clang's ``<float.h>``
- freestanding implementation; these macros were defined in C99 but Clang
- implements the macros as described by C23 in
+ freestanding implementation; these macros were defined in ``<math.h>`` in C99
+ but C23 added them to ``<float.h>`` in
`WG14 N2848 <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2848.pdf>`_.
Non-comprehensive list of changes in this release
diff --git a/clang/lib/Headers/float.h b/clang/lib/Headers/float.h
index 929c0854a865b..a0cfeb12862f7 100644
--- a/clang/lib/Headers/float.h
+++ b/clang/lib/Headers/float.h
@@ -95,10 +95,6 @@
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
(defined(__cplusplus) && __cplusplus >= 201103L)
#define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
-#if defined(__FINITE_MATH_ONLY__) && !__FINITE_MATH_ONLY__
-# define INFINITY (__builtin_infinity())
-# define NAN (__builtin_nan(""))
-#endif
#endif
#define FLT_ROUNDS (__builtin_flt_rounds())
#define FLT_RADIX __FLT_RADIX__
@@ -161,6 +157,13 @@
# define LDBL_HAS_SUBNORM __LDBL_HAS_DENORM__
#endif
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || \
+ !defined(__STRICT_ANSI__)
+ /* C23 5.2.5.3.3p29-30 */
+# define INFINITY (__builtin_inf())
+# define NAN (__builtin_nan(""))
+#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 8dfbc32521ade..b9e6e971545e5 100644
--- a/clang/test/Headers/float.c
+++ b/clang/test/Headers/float.c
@@ -111,35 +111,10 @@
#elif DECIMAL_DIG < 10
#error "Mandatory macro DECIMAL_DIG is invalid."
#endif
-
- #if __FINITE_MATH_ONLY__ == 0
- #ifndef INFINITY
- #error "Mandatory macro INFINITY is missing."
- #endif
- #ifndef NAN
- #error "Mandatory macro NAN is missing."
- #endif
- #else
- #ifdef INFINITY
- #error "Macro INFINITY should not be defined."
- #endif
-
- #ifdef NAN
- #error "Macro NAN should not be defined."
- #endif
- #endif
#else
#ifdef DECIMAL_DIG
#error "Macro DECIMAL_DIG should not be defined."
#endif
-
- #ifdef INFINITY
- #error "Macro INFINITY should not be defined."
- #endif
-
- #ifdef NAN
- #error "Macro NAN should not be defined."
- #endif
#endif
@@ -236,6 +211,21 @@
#error "Mandatory macros {FLT,DBL,LDBL}_MAX_10_EXP are invalid."
#endif
+#if __STDC_VERSION__ >= 202311L || !defined(__STRICT_ANSI__)
+ #ifndef INFINITY
+ #error "Mandatory macro INFINITY is missing."
+ #endif
+ #ifndef NAN
+ #error "Mandatory macro NAN is missing."
+ #endif
+#else
+ #ifdef INFINITY
+ #error "Macro INFINITY should not be defined."
+ #endif
+ #ifdef NAN
+ #error "Macro NAN should not be defined."
+ #endif
+#endif
/* Internal consistency checks */
_Static_assert(FLT_RADIX == __FLT_RADIX__, "");
@@ -273,3 +263,9 @@ _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__)) && __FINITE_MATH_ONLY__ == 0
+// Ensure INFINITY and NAN are suitable for use in a constant expression.
+float f1 = INFINITY;
+float f2 = NAN;
+#endif
>From 3f6278781a1cd8d2366e0c55cd19e559e6ee1549 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron at aaronballman.com>
Date: Mon, 1 Jul 2024 08:58:22 -0400
Subject: [PATCH 4/4] Fix undefines
---
clang/lib/Headers/float.h | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/clang/lib/Headers/float.h b/clang/lib/Headers/float.h
index a0cfeb12862f7..a565a33243df1 100644
--- a/clang/lib/Headers/float.h
+++ b/clang/lib/Headers/float.h
@@ -47,8 +47,6 @@
(defined(__cplusplus) && __cplusplus >= 201103L) || \
(__STDC_HOSTED__ && defined(_AIX) && defined(_ALL_SOURCE))
# undef DECIMAL_DIG
-# undef INFINITY
-# undef NAN
# endif
# undef FLT_DIG
# undef DBL_DIG
@@ -90,6 +88,12 @@
# endif
#endif
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 202311L) || \
+ !defined(__STRICT_ANSI__)
+# undef INFINITY
+# undef NAN
+#endif
+
/* Characteristics of floating point types, C99 5.2.4.2.2 */
#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
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