fixup! [libc][math][c23] Add fabsf16 C23 math function

Move _Float16 detection header to llvm-libc-macros/float16-macros.h.

Author: overmighty

libc/config/linux/api.td

@@ -60,7 +60,7 @@ def IntTypesAPI : PublicAPI<"inttypes.h"> {
 }
 
 def MathAPI : PublicAPI<"math.h"> {
-  let Types = ["double_t", "float_t", "float16", "float128"];
+  let Types = ["double_t", "float_t", "float128"];
 }
 
 def FenvAPI: PublicAPI<"fenv.h"> {

libc/include/llvm-libc-macros/CMakeLists.txt

@@ -91,6 +91,12 @@ add_macro_header(
     float-macros.h
 )
 
+add_macro_header(
+  float16_macros
+  HDR
+    float16-macros.h
+)
+
 add_macro_header(
   limits_macros
   HDR

libc/include/llvm-libc-macros/float16-macros.h

@@ -0,0 +1,17 @@
+//===-- Detection of _Float16 compiler builtin type -----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_MACROS_FLOAT16_MACROS_H
+#define LLVM_LIBC_MACROS_FLOAT16_MACROS_H
+
+#if defined(__FLT16_MANT_DIG__) &&                                             \
+    (!defined(__GNUC__) || __GNUC__ >= 13 || defined(__clang__))
+#define LIBC_TYPES_HAS_FLOAT16
+#endif
+
+#endif // LLVM_LIBC_MACROS_FLOAT16_MACROS_H

libc/include/math.h.def

@@ -10,6 +10,7 @@
 #define LLVM_LIBC_MATH_H
 
 #include "__llvm-libc-common.h"
+#include "llvm-libc-macros/float16-macros.h"
 #include "llvm-libc-macros/math-macros.h"
 #include "llvm-libc-types/float128.h"
 

libc/spec/stdc.td

@@ -378,7 +378,6 @@ def StdC : StandardSpec<"stdc"> {
       [
           NamedType<"float_t">,
           NamedType<"double_t">,
-          NamedType<"float16">,
           NamedType<"float128">,
       ],
       [], // Enumerations

libc/src/__support/macros/properties/CMakeLists.txt

@@ -34,5 +34,6 @@ add_header_library(
     .cpu_features
     .os
     libc.hdr.float_macros
+    libc.include.llvm-libc-macros.float16_macros
     libc.include.llvm-libc-types.float128
 )

libc/src/__support/macros/properties/types.h

@@ -11,8 +11,8 @@
 #define LLVM_LIBC_SRC___SUPPORT_MACROS_PROPERTIES_TYPES_H
 
 #include "hdr/float_macros.h"                      // LDBL_MANT_DIG
-#include "include/llvm-libc-types/float128.h"      // float128
-#include "include/llvm-libc-types/float16.h"       // LIBC_TYPES_HAS_FLOAT16
+#include "include/llvm-libc-macros/float16-macros.h" // LIBC_TYPES_HAS_FLOAT16
+#include "include/llvm-libc-types/float128.h"        // float128
 #include "src/__support/macros/properties/architectures.h"
 #include "src/__support/macros/properties/compiler.h"
 #include "src/__support/macros/properties/cpu_features.h"
@@ -40,7 +40,8 @@
 #endif // defined(__SIZEOF_INT128__)
 
 // -- float16 support ---------------------------------------------------------
-// LIBC_TYPES_HAS_FLOAT16 is provided by "include/llvm-libc-types/float16.h"
+// LIBC_TYPES_HAS_FLOAT16 is provided by
+// "include/llvm-libc-macros/float16-macros.h"
 #ifdef LIBC_TYPES_HAS_FLOAT16
 // Type alias for internal use.
 using float16 = _Float16;