[libc] Add implementations of fmax, fmaxf, and fmaxl.

Summary: Add implementations of fmax, fmaxf, and fmaxl.

Reviewers: sivachandra

Subscribers: mgorny, tschuett, libc-commits, ecnelises

Tags: #libc-project

Differential Revision: https://reviews.llvm.org/D84385

4 files changed, 256 insertions, 1 deletions

diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
index a6898b370621..3bd40f6b32f1 100644
--- a/libc/test/src/math/CMakeLists.txt
+++ b/libc/test/src/math/CMakeLists.txt
@@ -472,4 +472,40 @@ add_math_unittest(
     libc.include.math
     libc.src.math.fminl
     libc.utils.FPUtil.fputil
-)
\ No newline at end of file
+)
+
+add_math_unittest(
+  fmaxf_test
+  SUITE
+    libc_math_unittests
+  SRCS
+    fmaxf_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.fmaxf
+    libc.utils.FPUtil.fputil
+)
+
+add_math_unittest(
+  fmax_test
+  SUITE
+    libc_math_unittests
+  SRCS
+    fmax_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.fmax
+    libc.utils.FPUtil.fputil
+)
+
+add_math_unittest(
+  fmaxl_test
+  SUITE
+    libc_math_unittests
+  SRCS
+    fmaxl_test.cpp
+  DEPENDS
+    libc.include.math
+    libc.src.math.fmaxl
+    libc.utils.FPUtil.fputil
+)
diff --git a/libc/test/src/math/fmax_test.cpp b/libc/test/src/math/fmax_test.cpp
new file mode 100644
index 000000000000..8d1c6c276382
--- /dev/null
+++ b/libc/test/src/math/fmax_test.cpp
@@ -0,0 +1,73 @@
+//===-- Unittests for fmax -----------------------------------------------===//
+//
+// 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 "include/math.h"
+#include "src/math/fmax.h"
+#include "utils/FPUtil/FPBits.h"
+#include "utils/UnitTest/Test.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<double>;
+
+double nan = FPBits::buildNaN(1);
+double inf = FPBits::inf();
+double negInf = FPBits::negInf();
+
+TEST(FmaxTest, NaNArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmax(nan, inf));
+  EXPECT_EQ(negInf, __llvm_libc::fmax(negInf, nan));
+  EXPECT_EQ(0.0, __llvm_libc::fmax(nan, 0.0));
+  EXPECT_EQ(-0.0, __llvm_libc::fmax(-0.0, nan));
+  EXPECT_EQ(-1.2345, __llvm_libc::fmax(nan, -1.2345));
+  EXPECT_EQ(1.2345, __llvm_libc::fmax(1.2345, nan));
+  EXPECT_NE(isnan(__llvm_libc::fmax(nan, nan)), 0);
+}
+
+TEST(FmaxTest, InfArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmax(negInf, inf));
+  EXPECT_EQ(inf, __llvm_libc::fmax(inf, 0.0));
+  EXPECT_EQ(inf, __llvm_libc::fmax(-0.0, inf));
+  EXPECT_EQ(inf, __llvm_libc::fmax(inf, 1.2345));
+  EXPECT_EQ(inf, __llvm_libc::fmax(-1.2345, inf));
+}
+
+TEST(FmaxTest, NegInfArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmax(inf, negInf));
+  EXPECT_EQ(0.0, __llvm_libc::fmax(negInf, 0.0));
+  EXPECT_EQ(-0.0, __llvm_libc::fmax(-0.0, negInf));
+  EXPECT_EQ(-1.2345, __llvm_libc::fmax(negInf, -1.2345));
+  EXPECT_EQ(1.2345, __llvm_libc::fmax(1.2345, negInf));
+}
+
+TEST(FmaxTest, BothZero) {
+  EXPECT_EQ(0.0, __llvm_libc::fmax(0.0, 0.0));
+  EXPECT_EQ(0.0, __llvm_libc::fmax(-0.0, 0.0));
+  EXPECT_EQ(0.0, __llvm_libc::fmax(0.0, -0.0));
+  EXPECT_EQ(-0.0, __llvm_libc::fmax(-0.0, -0.0));
+}
+
+TEST(FmaxTest, InDoubleRange) {
+  using UIntType = FPBits::UIntType;
+  constexpr UIntType count = 10000001;
+  constexpr UIntType step = UIntType(-1) / count;
+  for (UIntType i = 0, v = 0, w = UIntType(-1); i <= count;
+       ++i, v += step, w -= step) {
+    double x = FPBits(v), y = FPBits(w);
+    if (isnan(x) || isinf(x))
+      continue;
+    if (isnan(y) || isinf(y))
+      continue;
+    if ((x == 0) && (y == 0))
+      continue;
+
+    if (x > y) {
+      ASSERT_EQ(x, __llvm_libc::fmax(x, y));
+    } else {
+      ASSERT_EQ(y, __llvm_libc::fmax(x, y));
+    }
+  }
+}
diff --git a/libc/test/src/math/fmaxf_test.cpp b/libc/test/src/math/fmaxf_test.cpp
new file mode 100644
index 000000000000..fe9eaad171bd
--- /dev/null
+++ b/libc/test/src/math/fmaxf_test.cpp
@@ -0,0 +1,73 @@
+//===-- Unittests for fmaxf -----------------------------------------------===//
+//
+// 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 "include/math.h"
+#include "src/math/fmaxf.h"
+#include "utils/FPUtil/FPBits.h"
+#include "utils/UnitTest/Test.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<float>;
+
+float nan = FPBits::buildNaN(1);
+float inf = FPBits::inf();
+float negInf = FPBits::negInf();
+
+TEST(FmaxfTest, NaNArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(nan, inf));
+  EXPECT_EQ(negInf, __llvm_libc::fmaxf(negInf, nan));
+  EXPECT_EQ(0.0f, __llvm_libc::fmaxf(nan, 0.0f));
+  EXPECT_EQ(-0.0f, __llvm_libc::fmaxf(-0.0f, nan));
+  EXPECT_EQ(-1.2345f, __llvm_libc::fmaxf(nan, -1.2345f));
+  EXPECT_EQ(1.2345f, __llvm_libc::fmaxf(1.2345f, nan));
+  EXPECT_NE(isnan(__llvm_libc::fmaxf(nan, nan)), 0);
+}
+
+TEST(FmaxfTest, InfArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(negInf, inf));
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(inf, 0.0f));
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(-0.0f, inf));
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(inf, 1.2345f));
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(-1.2345f, inf));
+}
+
+TEST(FmaxfTest, NegInfArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmaxf(inf, negInf));
+  EXPECT_EQ(0.0f, __llvm_libc::fmaxf(negInf, 0.0f));
+  EXPECT_EQ(-0.0f, __llvm_libc::fmaxf(-0.0f, negInf));
+  EXPECT_EQ(-1.2345f, __llvm_libc::fmaxf(negInf, -1.2345f));
+  EXPECT_EQ(1.2345f, __llvm_libc::fmaxf(1.2345f, negInf));
+}
+
+TEST(FmaxfTest, BothZero) {
+  EXPECT_EQ(0.0f, __llvm_libc::fmaxf(0.0f, 0.0f));
+  EXPECT_EQ(0.0f, __llvm_libc::fmaxf(-0.0f, 0.0f));
+  EXPECT_EQ(0.0f, __llvm_libc::fmaxf(0.0f, -0.0f));
+  EXPECT_EQ(-0.0f, __llvm_libc::fmaxf(-0.0f, -0.0f));
+}
+
+TEST(FmaxfTest, InFloatRange) {
+  using UIntType = FPBits::UIntType;
+  constexpr UIntType count = 10000001;
+  constexpr UIntType step = UIntType(-1) / count;
+  for (UIntType i = 0, v = 0, w = UIntType(-1); i <= count;
+       ++i, v += step, w -= step) {
+    float x = FPBits(v), y = FPBits(w);
+    if (isnan(x) || isinf(x))
+      continue;
+    if (isnan(y) || isinf(y))
+      continue;
+    if ((x == 0) && (y == 0))
+      continue;
+
+    if (x > y) {
+      ASSERT_EQ(x, __llvm_libc::fmaxf(x, y));
+    } else {
+      ASSERT_EQ(y, __llvm_libc::fmaxf(x, y));
+    }
+  }
+}
diff --git a/libc/test/src/math/fmaxl_test.cpp b/libc/test/src/math/fmaxl_test.cpp
new file mode 100644
index 000000000000..9c7aa21582eb
--- /dev/null
+++ b/libc/test/src/math/fmaxl_test.cpp
@@ -0,0 +1,73 @@
+//===-- Unittests for fmaxl -----------------------------------------------===//
+//
+// 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 "include/math.h"
+#include "src/math/fmaxl.h"
+#include "utils/FPUtil/FPBits.h"
+#include "utils/UnitTest/Test.h"
+
+using FPBits = __llvm_libc::fputil::FPBits<long double>;
+
+long double nan = FPBits::buildNaN(1);
+long double inf = FPBits::inf();
+long double negInf = FPBits::negInf();
+
+TEST(FmaxlTest, NaNArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(nan, inf));
+  EXPECT_EQ(negInf, __llvm_libc::fmaxl(negInf, nan));
+  EXPECT_EQ(0.0L, __llvm_libc::fmaxl(nan, 0.0L));
+  EXPECT_EQ(-0.0L, __llvm_libc::fmaxl(-0.0L, nan));
+  EXPECT_EQ(-1.2345L, __llvm_libc::fmaxl(nan, -1.2345L));
+  EXPECT_EQ(1.2345L, __llvm_libc::fmaxl(1.2345L, nan));
+  EXPECT_NE(isnan(__llvm_libc::fmaxl(nan, nan)), 0);
+}
+
+TEST(FmaxlTest, InfArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(negInf, inf));
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(inf, 0.0L));
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(-0.0L, inf));
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(inf, 1.2345L));
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(-1.2345L, inf));
+}
+
+TEST(FmaxlTest, NegInfArg) {
+  EXPECT_EQ(inf, __llvm_libc::fmaxl(inf, negInf));
+  EXPECT_EQ(0.0L, __llvm_libc::fmaxl(negInf, 0.0L));
+  EXPECT_EQ(-0.0L, __llvm_libc::fmaxl(-0.0L, negInf));
+  EXPECT_EQ(-1.2345L, __llvm_libc::fmaxl(negInf, -1.2345L));
+  EXPECT_EQ(1.2345L, __llvm_libc::fmaxl(1.2345L, negInf));
+}
+
+TEST(FmaxlTest, BothZero) {
+  EXPECT_EQ(0.0L, __llvm_libc::fmaxl(0.0L, 0.0L));
+  EXPECT_EQ(0.0L, __llvm_libc::fmaxl(-0.0L, 0.0L));
+  EXPECT_EQ(0.0L, __llvm_libc::fmaxl(0.0L, -0.0L));
+  EXPECT_EQ(-0.0L, __llvm_libc::fmaxl(-0.0L, -0.0L));
+}
+
+TEST(FmaxlTest, InLongDoubleRange) {
+  using UIntType = FPBits::UIntType;
+  constexpr UIntType count = 10000001;
+  constexpr UIntType step = UIntType(-1) / count;
+  for (UIntType i = 0, v = 0, w = UIntType(-1); i <= count;
+       ++i, v += step, w -= step) {
+    long double x = FPBits(v), y = FPBits(w);
+    if (isnan(x) || isinf(x))
+      continue;
+    if (isnan(y) || isinf(y))
+      continue;
+    if ((x == 0) && (y == 0))
+      continue;
+
+    if (x > y) {
+      ASSERT_EQ(x, __llvm_libc::fmaxl(x, y));
+    } else {
+      ASSERT_EQ(y, __llvm_libc::fmaxl(x, y));
+    }
+  }
+}