[libc][math][c23] Add remainderf16 C23 math function

Author: overmighty

libc/config/linux/aarch64/entrypoints.txt

@@ -536,6 +536,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     # clang-12 and after: https://godbolt.org/z/8ceT9454c
     # libc.src.math.nexttowardf16
     libc.src.math.nextupf16
+    libc.src.math.remainderf16
     libc.src.math.rintf16
     libc.src.math.roundf16
     libc.src.math.roundevenf16

libc/config/linux/x86_64/entrypoints.txt

@@ -566,6 +566,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.nextdownf16
     libc.src.math.nexttowardf16
     libc.src.math.nextupf16
+    libc.src.math.remainderf16
     libc.src.math.rintf16
     libc.src.math.roundf16
     libc.src.math.roundevenf16

libc/docs/math/index.rst

@@ -198,7 +198,7 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | nextup           | |check|          | |check|         | |check|                | |check|              | |check|                | 7.12.11.5              | F.10.8.5                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| remainder        | |check|          | |check|         | |check|                |                      |                        | 7.12.10.2              | F.10.7.2                   |
+| remainder        | |check|          | |check|         | |check|                | |check|              |                        | 7.12.10.2              | F.10.7.2                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | remquo           | |check|          | |check|         | |check|                |                      | |check|                | 7.12.10.3              | F.10.7.3                   |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+

libc/spec/stdc.td

@@ -581,9 +581,10 @@ def StdC : StandardSpec<"stdc"> {
           FunctionSpec<"exp10", RetValSpec<DoubleType>, [ArgSpec<DoubleType>]>,
           FunctionSpec<"exp10f", RetValSpec<FloatType>, [ArgSpec<FloatType>]>,
 
-          FunctionSpec<"remainderf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,
           FunctionSpec<"remainder", RetValSpec<DoubleType>, [ArgSpec<DoubleType>, ArgSpec<DoubleType>]>,
+          FunctionSpec<"remainderf", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>]>,
           FunctionSpec<"remainderl", RetValSpec<LongDoubleType>, [ArgSpec<LongDoubleType>, ArgSpec<LongDoubleType>]>,
+          GuardedFunctionSpec<"remainderf16", RetValSpec<Float16Type>, [ArgSpec<Float16Type>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
 
           FunctionSpec<"remquof", RetValSpec<FloatType>, [ArgSpec<FloatType>, ArgSpec<FloatType>, ArgSpec<IntPtr>]>,
           GuardedFunctionSpec<"remquof128", RetValSpec<Float128Type>, [ArgSpec<Float128Type>, ArgSpec<Float128Type>, ArgSpec<IntPtr>], "LIBC_TYPES_HAS_FLOAT128">,

libc/src/__support/FPUtil/NormalFloat.h

@@ -52,7 +52,7 @@ template <typename T> struct NormalFloat {
       return;
 
     unsigned normalization_shift = evaluate_normalization_shift(mantissa);
-    mantissa = mantissa << normalization_shift;
+    mantissa <<= normalization_shift;
     exponent -= normalization_shift;
   }
 

libc/src/math/CMakeLists.txt

@@ -315,6 +315,7 @@ add_math_entrypoint_object(powf)
 add_math_entrypoint_object(remainder)
 add_math_entrypoint_object(remainderf)
 add_math_entrypoint_object(remainderl)
+add_math_entrypoint_object(remainderf16)
 
 add_math_entrypoint_object(remquo)
 add_math_entrypoint_object(remquof)

libc/src/math/generic/CMakeLists.txt

@@ -2570,6 +2570,19 @@ add_entrypoint_object(
     -O2
 )
 
+add_entrypoint_object(
+  remainderf16
+  SRCS
+    remainderf16.cpp
+  HDRS
+    ../remainderf16.h
+  DEPENDS
+    libc.src.__support.macros.properties.types
+    libc.src.__support.FPUtil.division_and_remainder_operations
+  COMPILE_OPTIONS
+    -O2
+)
+
 add_entrypoint_object(
   hypotf
   SRCS

libc/src/math/generic/remainderf16.cpp

@@ -0,0 +1,20 @@
+//===-- Implementation of remainderf16 function ---------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/math/remainderf16.h"
+#include "src/__support/FPUtil/DivisionAndRemainderOperations.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(float16, remainderf16, (float16 x, float16 y)) {
+  int quotient;
+  return fputil::remquo(x, y, quotient);
+}
+
+} // namespace LIBC_NAMESPACE

libc/src/math/remainderf16.h

@@ -0,0 +1,20 @@
+//===-- Implementation header for remainderf16 ------------------*- C++ -*-===//
+//
+// 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_SRC_MATH_REMAINDERF16_H
+#define LLVM_LIBC_SRC_MATH_REMAINDERF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+float16 remainderf16(float16 x, float16 y);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_REMAINDERF16_H