[libc][math][c23] Add setpayloadsigf16 C23 math function

overmighty · overmighty · commit f9fb6c99ca96 · 2024-06-11T20:22:41.000+02:00
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -543,6 +543,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.roundf16
     libc.src.math.roundevenf16
     libc.src.math.setpayloadf16
+    libc.src.math.setpayloadsigf16
     libc.src.math.totalorderf16
     libc.src.math.totalordermagf16
     libc.src.math.truncf16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -573,6 +573,7 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.roundf16
     libc.src.math.roundevenf16
     libc.src.math.setpayloadf16
+    libc.src.math.setpayloadsigf16
     libc.src.math.totalorderf16
     libc.src.math.totalordermagf16
     libc.src.math.truncf16
diff --git a/libc/docs/c23.rst b/libc/docs/c23.rst
@@ -46,6 +46,7 @@ Additions:
   * totalordermag* |check|
   * getpayload* |check|
   * setpayload* |check|
+  * setpayloadsig* |check|
   * iscannonical
   * issignaling
   * issubnormal
diff --git a/libc/docs/math/index.rst b/libc/docs/math/index.rst
@@ -214,6 +214,8 @@ Basic Operations
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | setpayload       |                  |                 |                        | |check|              |                        | F.10.13.2              | N/A                        |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
+| setpayloadsig    |                  |                 |                        | |check|              |                        | F.10.13.3              | N/A                        |
++------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | totalorder       |                  |                 |                        | |check|              |                        | F.10.12.1              | N/A                        |
 +------------------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | totalordermag    |                  |                 |                        | |check|              |                        | F.10.12.2              | N/A                        |
diff --git a/libc/spec/stdc.td b/libc/spec/stdc.td
@@ -718,6 +718,8 @@ def StdC : StandardSpec<"stdc"> {
           GuardedFunctionSpec<"getpayloadf16", RetValSpec<Float16Type>, [ArgSpec<Float16Ptr>], "LIBC_TYPES_HAS_FLOAT16">,
 
           GuardedFunctionSpec<"setpayloadf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
+
+          GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,
       ]
   >;
 
diff --git a/libc/src/__support/FPUtil/BasicOperations.h b/libc/src/__support/FPUtil/BasicOperations.h
@@ -276,13 +276,15 @@ LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, T> getpayload(T x) {
   return T(x_bits.uintval() & (FPBits::FRACTION_MASK >> 1));
 }
 
-template <typename T>
+template <bool IsSignaling, typename T>
 LIBC_INLINE cpp::enable_if_t<cpp::is_floating_point_v<T>, bool>
 setpayload(T *res, T pl) {
   using FPBits = FPBits<T>;
   FPBits pl_bits(pl);
 
-  if (pl_bits.is_zero()) {
+  // Signaling NaNs don't have the mantissa's MSB set to 1, so they need a
+  // non-zero payload to distinguish them from infinities.
+  if (!IsSignaling && pl_bits.is_zero()) {
     *res = FPBits::quiet_nan(Sign::POS).get_val();
     return false;
   }
@@ -297,7 +299,11 @@ setpayload(T *res, T pl) {
 
   using StorageType = typename FPBits::StorageType;
   StorageType v(pl_bits.get_explicit_mantissa() >> (FPBits::SIG_LEN - pl_exp));
-  *res = FPBits::quiet_nan(Sign::POS, v).get_val();
+
+  if constexpr (IsSignaling)
+    *res = FPBits::signaling_nan(Sign::POS, v).get_val();
+  else
+    *res = FPBits::quiet_nan(Sign::POS, v).get_val();
   return false;
 }
 
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
@@ -350,6 +350,8 @@ add_math_entrypoint_object(scalbnf128)
 
 add_math_entrypoint_object(setpayloadf16)
 
+add_math_entrypoint_object(setpayloadsigf16)
+
 add_math_entrypoint_object(sincos)
 add_math_entrypoint_object(sincosf)
 
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
@@ -3625,3 +3625,15 @@ add_entrypoint_object(
   COMPILE_OPTIONS
     -O3
 )
+
+add_entrypoint_object(
+  setpayloadsigf16
+  SRCS
+    setpayloadsigf16.cpp
+  HDRS
+    ../setpayloadsigf16.h
+  DEPENDS
+    libc.src.__support.FPUtil.basic_operations
+  COMPILE_OPTIONS
+    -O3
+)
diff --git a/libc/src/math/generic/setpayloadf16.cpp b/libc/src/math/generic/setpayloadf16.cpp
@@ -13,7 +13,7 @@
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(int, setpayloadf16, (float16 * res, float16 pl)) {
-  return static_cast<int>(fputil::setpayload(res, pl));
+  return static_cast<int>(fputil::setpayload</*IsSignaling=*/false>(res, pl));
 }
 
 } // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/generic/setpayloadsigf16.cpp b/libc/src/math/generic/setpayloadsigf16.cpp
@@ -0,0 +1,19 @@
+//===-- Implementation of setpayloadsigf16 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/setpayloadsigf16.h"
+#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+
+LLVM_LIBC_FUNCTION(int, setpayloadsigf16, (float16 * res, float16 pl)) {
+  return static_cast<int>(fputil::setpayload</*IsSignaling=*/true>(res, pl));
+}
+
+} // namespace LIBC_NAMESPACE
diff --git a/libc/src/math/setpayloadsigf16.h b/libc/src/math/setpayloadsigf16.h
@@ -0,0 +1,20 @@
+//===-- Implementation header for setpayloadsigf16 --------------*- 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_SETPAYLOADSIGF16_H
+#define LLVM_LIBC_SRC_MATH_SETPAYLOADSIGF16_H
+
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE {
+
+int setpayloadsigf16(float16 *res, float16 pl);
+
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC_MATH_SETPAYLOADSIGF16_H
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
@@ -3567,3 +3567,15 @@ add_fp_unittest(
   DEPENDS
     libc.src.math.setpayloadf16
 )
+
+add_fp_unittest(
+  setpayloadsigf16_test
+  SUITE
+    libc-math-smoke-tests
+  SRCS
+    setpayloadsigf16_test.cpp
+  HDRS
+    SetPayloadSigTest.h
+  DEPENDS
+    libc.src.math.setpayloadsigf16
+)
diff --git a/libc/test/src/math/smoke/SetPayloadSigTest.h b/libc/test/src/math/smoke/SetPayloadSigTest.h
@@ -0,0 +1,74 @@
+//===-- Utility class to test flavors of setpayloadsig ----------*- 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 LIBC_TEST_SRC_MATH_SMOKE_SETPAYLOADSIGTEST_H
+#define LIBC_TEST_SRC_MATH_SMOKE_SETPAYLOADSIGTEST_H
+
+#include "test/UnitTest/FEnvSafeTest.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "test/UnitTest/Test.h"
+
+template <typename T>
+class SetPayloadSigTestTemplate : public LIBC_NAMESPACE::testing::FEnvSafeTest {
+
+  DECLARE_SPECIAL_CONSTANTS(T)
+
+public:
+  typedef int (*SetPayloadSigFunc)(T *, T);
+
+  void testInvalidPayloads(SetPayloadSigFunc func) {
+    T res;
+
+    EXPECT_EQ(1, func(&res, T(aNaN)));
+    EXPECT_EQ(1, func(&res, T(neg_aNaN)));
+    EXPECT_EQ(1, func(&res, T(inf)));
+    EXPECT_EQ(1, func(&res, T(neg_inf)));
+    EXPECT_EQ(1, func(&res, T(0.0)));
+    EXPECT_EQ(1, func(&res, T(-0.0)));
+    EXPECT_EQ(1, func(&res, T(0.1)));
+    EXPECT_EQ(1, func(&res, T(-0.1)));
+    EXPECT_EQ(1, func(&res, T(-1.0)));
+    EXPECT_EQ(1, func(&res, T(0x42.1p+0)));
+    EXPECT_EQ(1, func(&res, T(-0x42.1p+0)));
+    EXPECT_EQ(1, func(&res, T(StorageType(1) << (FPBits::FRACTION_LEN - 1))));
+  }
+
+  void testValidPayloads(SetPayloadSigFunc func) {
+    T res;
+
+    EXPECT_EQ(0, func(&res, T(1.0)));
+    EXPECT_TRUE(FPBits(res).is_signaling_nan());
+    EXPECT_EQ(FPBits::signaling_nan(Sign::POS, 1).uintval(),
+              FPBits(res).uintval());
+
+    EXPECT_EQ(0, func(&res, T(0x42.0p+0)));
+    EXPECT_TRUE(FPBits(res).is_signaling_nan());
+    EXPECT_EQ(FPBits::signaling_nan(Sign::POS, 0x42).uintval(),
+              FPBits(res).uintval());
+
+    EXPECT_EQ(0, func(&res, T(0x123.0p+0)));
+    EXPECT_TRUE(FPBits(res).is_signaling_nan());
+    EXPECT_EQ(FPBits::signaling_nan(Sign::POS, 0x123).uintval(),
+              FPBits(res).uintval());
+
+    EXPECT_EQ(0, func(&res, T(FPBits::FRACTION_MASK >> 1)));
+    EXPECT_TRUE(FPBits(res).is_signaling_nan());
+    EXPECT_EQ(
+        FPBits::signaling_nan(Sign::POS, FPBits::FRACTION_MASK >> 1).uintval(),
+        FPBits(res).uintval());
+  }
+};
+
+#define LIST_SETPAYLOADSIG_TESTS(T, func)                                      \
+  using LlvmLibcSetPayloadSigTest = SetPayloadSigTestTemplate<T>;              \
+  TEST_F(LlvmLibcSetPayloadSigTest, InvalidPayloads) {                         \
+    testInvalidPayloads(&func);                                                \
+  }                                                                            \
+  TEST_F(LlvmLibcSetPayloadSigTest, ValidPayloads) { testValidPayloads(&func); }
+
+#endif // LIBC_TEST_SRC_MATH_SMOKE_SETPAYLOADSIGTEST_H
diff --git a/libc/test/src/math/smoke/SetPayloadTest.h b/libc/test/src/math/smoke/SetPayloadTest.h
@@ -40,16 +40,25 @@ class SetPayloadTestTemplate : public LIBC_NAMESPACE::testing::FEnvSafeTest {
     T res;
 
     EXPECT_EQ(0, func(&res, T(0.0)));
+    EXPECT_TRUE(FPBits(res).is_quiet_nan());
     EXPECT_EQ(FPBits(aNaN).uintval(), FPBits(res).uintval());
+
     EXPECT_EQ(0, func(&res, T(1.0)));
+    EXPECT_TRUE(FPBits(res).is_quiet_nan());
     EXPECT_EQ(FPBits::quiet_nan(Sign::POS, 1).uintval(), FPBits(res).uintval());
+
     EXPECT_EQ(0, func(&res, T(0x42.0p+0)));
+    EXPECT_TRUE(FPBits(res).is_quiet_nan());
     EXPECT_EQ(FPBits::quiet_nan(Sign::POS, 0x42).uintval(),
               FPBits(res).uintval());
+
     EXPECT_EQ(0, func(&res, T(0x123.0p+0)));
+    EXPECT_TRUE(FPBits(res).is_quiet_nan());
     EXPECT_EQ(FPBits::quiet_nan(Sign::POS, 0x123).uintval(),
               FPBits(res).uintval());
+
     EXPECT_EQ(0, func(&res, T(FPBits::FRACTION_MASK >> 1)));
+    EXPECT_TRUE(FPBits(res).is_quiet_nan());
     EXPECT_EQ(
         FPBits::quiet_nan(Sign::POS, FPBits::FRACTION_MASK >> 1).uintval(),
         FPBits(res).uintval());
diff --git a/libc/test/src/math/smoke/setpayloadsigf16_test.cpp b/libc/test/src/math/smoke/setpayloadsigf16_test.cpp
@@ -0,0 +1,13 @@
+//===-- Unittests for setpayloadsigf16 ------------------------------------===//
+//
+// 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 "SetPayloadSigTest.h"
+
+#include "src/math/setpayloadsigf16.h"
+
+LIST_SETPAYLOADSIG_TESTS(float16, LIBC_NAMESPACE::setpayloadsigf16)

Original file line number	Diff line number	Diff line change
`@@ -718,6 +718,8 @@ def StdC : StandardSpec<"stdc"> {`
`718`	`718`	`GuardedFunctionSpec<"getpayloadf16", RetValSpec<Float16Type>, [ArgSpec<Float16Ptr>], "LIBC_TYPES_HAS_FLOAT16">,`
`719`	`719`
`720`	`720`	`GuardedFunctionSpec<"setpayloadf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,`
	`721`	`+`
	`722`	`+ GuardedFunctionSpec<"setpayloadsigf16", RetValSpec<IntType>, [ArgSpec<Float16Ptr>, ArgSpec<Float16Type>], "LIBC_TYPES_HAS_FLOAT16">,`
`721`	`723`	`]`
`722`	`724`	`>;`
`723`	`725`
Original file line number	Diff line number	Diff line change
`@@ -13,7 +13,7 @@`
`13`	`13`	`namespace LIBC_NAMESPACE {`
`14`	`14`
`15`	`15`	`LLVM_LIBC_FUNCTION(int, setpayloadf16, (float16 * res, float16 pl)) {`
`16`		`- return static_cast<int>(fputil::setpayload(res, pl));`
	`16`	`+ return static_cast<int>(fputil::setpayload</IsSignaling=/false>(res, pl));`
`17`	`17`	`}`
`18`	`18`
`19`	`19`	`} // namespace LIBC_NAMESPACE`