[libc-commits] [libc] [libc] Fix value in Atan2f128 (PR #215023)
via libc-commits
libc-commits at lists.llvm.org
Sat Aug 8 14:18:10 PDT 2026
https://github.com/Sukumarsawant updated https://github.com/llvm/llvm-project/pull/215023
>From 071ad39c90b08638fa91b8ea9c232e1fa363497e Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Sun, 9 Aug 2026 02:04:43 +0530
Subject: [PATCH 1/3] feat: fix value and add test
---
libc/src/__support/math/atan2f128.h | 2 +-
libc/test/src/math/smoke/atan2f128_test.cpp | 2 ++
2 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/libc/src/__support/math/atan2f128.h b/libc/src/__support/math/atan2f128.h
index f99de5be3472c..3c0b2620848ca 100644
--- a/libc/src/__support/math/atan2f128.h
+++ b/libc/src/__support/math/atan2f128.h
@@ -97,7 +97,7 @@ LIBC_INLINE float128 atan2f128(float128 y, float128 x) {
constexpr DFloat128 PI_OVER_4 = {Sign::POS, -128,
0xc90fdaa2'2168c234'c4c6628b'80dc1cd1_u128};
constexpr DFloat128 THREE_PI_OVER_4 = {
- Sign::POS, -128, 0x96cbe3f9'990e91a7'9394c9e8'a0a5159d_u128};
+ Sign::POS, -126, 0x96cbe3f9'990e91a7'9394c9e8'a0a5159d_u128};
// Adjustment for constant term:
// CONST_ADJ[x_sign][y_sign][recip]
diff --git a/libc/test/src/math/smoke/atan2f128_test.cpp b/libc/test/src/math/smoke/atan2f128_test.cpp
index 28b15ae71cac8..0d23c6e464e96 100644
--- a/libc/test/src/math/smoke/atan2f128_test.cpp
+++ b/libc/test/src/math/smoke/atan2f128_test.cpp
@@ -19,6 +19,8 @@ TEST_F(LlvmLibcAtan2f128Test, SpecialNumbers) {
EXPECT_FP_EQ_ALL_ROUNDING(neg_zero,
LIBC_NAMESPACE::atan2f128(neg_zero, zero));
EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::atan2f128(1.0, inf));
+ EXPECT_FP_EQ_ALL_ROUNDING(0x1.2d97c7f3321d234f272993d1414ap+1q,
+ LIBC_NAMESPACE::atan2f128(inf, neg_inf));
EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::atan2f128(-1.0, inf));
float128 x = 0x1.ffffffffffffffffffffffffffe7p1q;
>From 22aaf3833b8d4b91af3156dff8841fc5e4fd0802 Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Sun, 9 Aug 2026 02:18:26 +0530
Subject: [PATCH 2/3] remove all_rounding
---
libc/test/src/math/smoke/atan2f128_test.cpp | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/libc/test/src/math/smoke/atan2f128_test.cpp b/libc/test/src/math/smoke/atan2f128_test.cpp
index 0d23c6e464e96..0b135c5166d6a 100644
--- a/libc/test/src/math/smoke/atan2f128_test.cpp
+++ b/libc/test/src/math/smoke/atan2f128_test.cpp
@@ -19,8 +19,6 @@ TEST_F(LlvmLibcAtan2f128Test, SpecialNumbers) {
EXPECT_FP_EQ_ALL_ROUNDING(neg_zero,
LIBC_NAMESPACE::atan2f128(neg_zero, zero));
EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::atan2f128(1.0, inf));
- EXPECT_FP_EQ_ALL_ROUNDING(0x1.2d97c7f3321d234f272993d1414ap+1q,
- LIBC_NAMESPACE::atan2f128(inf, neg_inf));
EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::atan2f128(-1.0, inf));
float128 x = 0x1.ffffffffffffffffffffffffffe7p1q;
@@ -28,6 +26,9 @@ TEST_F(LlvmLibcAtan2f128Test, SpecialNumbers) {
float128 r = 0x1.921fb54442d18469898cc51701b3p-1q;
EXPECT_FP_EQ(r, LIBC_NAMESPACE::atan2f128(x, y));
+ EXPECT_FP_EQ(0x1.2d97c7f3321d234f272993d1414ap+1q,
+ LIBC_NAMESPACE::atan2f128(inf, neg_inf));
+
x = -0x1.f122e07fff556143p+3524q;
y = 0x1.f122e07fff55615b75p+6316q;
r = -0x1.ffffffffffffffe6cfcdc604fc99p-2793q;
>From 96d031c6812b5dac4bd29f68f03adb79bb3caaf2 Mon Sep 17 00:00:00 2001
From: Sukumarsawant <sawantsukumar at gmail.com>
Date: Sun, 9 Aug 2026 02:47:54 +0530
Subject: [PATCH 3/3] add tests for atan2(double,f16,f and f128)
---
libc/test/src/math/smoke/atan2_test.cpp | 18 ++++++++++++++
libc/test/src/math/smoke/atan2f128_test.cpp | 26 ++++++++++++++++-----
libc/test/src/math/smoke/atan2f16_test.cpp | 23 ++++++++++++++++++
libc/test/src/math/smoke/atan2f_test.cpp | 18 ++++++++++++++
4 files changed, 79 insertions(+), 6 deletions(-)
diff --git a/libc/test/src/math/smoke/atan2_test.cpp b/libc/test/src/math/smoke/atan2_test.cpp
index a79845fa0303d..8b2bc78a8da60 100644
--- a/libc/test/src/math/smoke/atan2_test.cpp
+++ b/libc/test/src/math/smoke/atan2_test.cpp
@@ -13,6 +13,24 @@
using LlvmLibcAtan2Test = LIBC_NAMESPACE::testing::FPTest<double>;
TEST_F(LlvmLibcAtan2Test, SpecialNumbers) {
+ constexpr double PI = 0x1.921fb54442d18p+1;
+ constexpr double PI_OVER_2 = 0x1.921fb54442d18p+0;
+ constexpr double PI_OVER_4 = 0x1.921fb54442d18p-1;
+ constexpr double THREE_PI_OVER_4 = 0x1.2d97c7f3321d2p+1;
+
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2(zero, neg_zero));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2(neg_zero, neg_zero));
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2(zero, neg_inf));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2(neg_zero, neg_inf));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2(inf, zero));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2(inf, neg_zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2(neg_inf, zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2(neg_inf, neg_zero));
+ EXPECT_FP_EQ(PI_OVER_4, LIBC_NAMESPACE::atan2(inf, inf));
+ EXPECT_FP_EQ(-PI_OVER_4, LIBC_NAMESPACE::atan2(neg_inf, inf));
+ EXPECT_FP_EQ(THREE_PI_OVER_4, LIBC_NAMESPACE::atan2(inf, neg_inf));
+ EXPECT_FP_EQ(-THREE_PI_OVER_4, LIBC_NAMESPACE::atan2(neg_inf, neg_inf));
+
EXPECT_FP_EQ_WITH_EXCEPTION(aNaN, LIBC_NAMESPACE::atan2(sNaN, sNaN),
FE_INVALID);
EXPECT_MATH_ERRNO(0);
diff --git a/libc/test/src/math/smoke/atan2f128_test.cpp b/libc/test/src/math/smoke/atan2f128_test.cpp
index 0b135c5166d6a..82feb28173ff6 100644
--- a/libc/test/src/math/smoke/atan2f128_test.cpp
+++ b/libc/test/src/math/smoke/atan2f128_test.cpp
@@ -13,11 +13,28 @@
using LlvmLibcAtan2f128Test = LIBC_NAMESPACE::testing::FPTest<float128>;
TEST_F(LlvmLibcAtan2f128Test, SpecialNumbers) {
+ constexpr float128 PI = 0x1.921fb54442d18469898cc51701b8p+1q;
+ constexpr float128 PI_OVER_2 = 0x1.921fb54442d18469898cc51701b8p+0q;
+ constexpr float128 PI_OVER_4 = 0x1.921fb54442d18469898cc51701b8p-1q;
+ constexpr float128 THREE_PI_OVER_4 = 0x1.2d97c7f3321d234f272993d1414ap+1q;
+
+ EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::atan2f128(zero, inf));
+ EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::atan2f128(neg_zero, inf));
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2f128(zero, neg_zero));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2f128(neg_zero, neg_zero));
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2f128(zero, neg_inf));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2f128(neg_zero, neg_inf));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2f128(inf, zero));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2f128(inf, neg_zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2f128(neg_inf, zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2f128(neg_inf, neg_zero));
+ EXPECT_FP_EQ(PI_OVER_4, LIBC_NAMESPACE::atan2f128(inf, inf));
+ EXPECT_FP_EQ(-PI_OVER_4, LIBC_NAMESPACE::atan2f128(neg_inf, inf));
+ EXPECT_FP_EQ(THREE_PI_OVER_4, LIBC_NAMESPACE::atan2f128(inf, neg_inf));
+ EXPECT_FP_EQ(-THREE_PI_OVER_4, LIBC_NAMESPACE::atan2f128(neg_inf, neg_inf));
+
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::atan2f128(aNaN, zero));
EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::atan2f128(1.0, aNaN));
- EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::atan2f128(zero, zero));
- EXPECT_FP_EQ_ALL_ROUNDING(neg_zero,
- LIBC_NAMESPACE::atan2f128(neg_zero, zero));
EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::atan2f128(1.0, inf));
EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::atan2f128(-1.0, inf));
@@ -26,9 +43,6 @@ TEST_F(LlvmLibcAtan2f128Test, SpecialNumbers) {
float128 r = 0x1.921fb54442d18469898cc51701b3p-1q;
EXPECT_FP_EQ(r, LIBC_NAMESPACE::atan2f128(x, y));
- EXPECT_FP_EQ(0x1.2d97c7f3321d234f272993d1414ap+1q,
- LIBC_NAMESPACE::atan2f128(inf, neg_inf));
-
x = -0x1.f122e07fff556143p+3524q;
y = 0x1.f122e07fff55615b75p+6316q;
r = -0x1.ffffffffffffffe6cfcdc604fc99p-2793q;
diff --git a/libc/test/src/math/smoke/atan2f16_test.cpp b/libc/test/src/math/smoke/atan2f16_test.cpp
index dd2dd90240378..cafc6842e6193 100644
--- a/libc/test/src/math/smoke/atan2f16_test.cpp
+++ b/libc/test/src/math/smoke/atan2f16_test.cpp
@@ -20,6 +20,29 @@ static constexpr float16 neg_one =
.get_val();
TEST_F(LlvmLibcAtan2f16Test, SpecialNumbers) {
+ constexpr float16 PI = static_cast<float16>(0x1.92p+1);
+ constexpr float16 PI_OVER_2 = static_cast<float16>(0x1.92p+0);
+ constexpr float16 PI_OVER_4 = static_cast<float16>(0x1.92p-1);
+ constexpr float16 THREE_PI_OVER_4 = static_cast<float16>(0x1.2d8p+1);
+
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2f16(zero, neg_zero));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2f16(neg_zero, neg_zero));
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2f16(zero, neg_inf));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2f16(neg_zero, neg_inf));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2f16(inf, zero));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2f16(inf, neg_zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2f16(neg_inf, zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2f16(neg_inf, neg_zero));
+ EXPECT_FP_EQ(PI_OVER_4, LIBC_NAMESPACE::atan2f16(inf, inf));
+ EXPECT_FP_EQ(-PI_OVER_4, LIBC_NAMESPACE::atan2f16(neg_inf, inf));
+ EXPECT_FP_EQ(THREE_PI_OVER_4, LIBC_NAMESPACE::atan2f16(inf, neg_inf));
+ EXPECT_FP_EQ(-THREE_PI_OVER_4, LIBC_NAMESPACE::atan2f16(neg_inf, neg_inf));
+
+ EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::atan2f16(aNaN, zero));
+ EXPECT_FP_EQ_ALL_ROUNDING(aNaN, LIBC_NAMESPACE::atan2f16(1.0, aNaN));
+ EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::atan2f16(1.0, inf));
+ EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::atan2f16(-1.0, inf));
+
EXPECT_FP_EQ_WITH_EXCEPTION(aNaN, LIBC_NAMESPACE::atan2f16(sNaN, sNaN),
FE_INVALID);
EXPECT_MATH_ERRNO(0);
diff --git a/libc/test/src/math/smoke/atan2f_test.cpp b/libc/test/src/math/smoke/atan2f_test.cpp
index 83173c6744622..69802fda68689 100644
--- a/libc/test/src/math/smoke/atan2f_test.cpp
+++ b/libc/test/src/math/smoke/atan2f_test.cpp
@@ -15,6 +15,24 @@
using LlvmLibcAtan2fTest = LIBC_NAMESPACE::testing::FPTest<float>;
TEST_F(LlvmLibcAtan2fTest, SpecialNumbers) {
+ constexpr float PI = 0x1.921fb6p+1f;
+ constexpr float PI_OVER_2 = 0x1.921fb6p+0f;
+ constexpr float PI_OVER_4 = 0x1.921fb6p-1f;
+ constexpr float THREE_PI_OVER_4 = 0x1.2d97c8p+1f;
+
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2f(zero, neg_zero));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2f(neg_zero, neg_zero));
+ EXPECT_FP_EQ(PI, LIBC_NAMESPACE::atan2f(zero, neg_inf));
+ EXPECT_FP_EQ(-PI, LIBC_NAMESPACE::atan2f(neg_zero, neg_inf));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2f(inf, zero));
+ EXPECT_FP_EQ(PI_OVER_2, LIBC_NAMESPACE::atan2f(inf, neg_zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2f(neg_inf, zero));
+ EXPECT_FP_EQ(-PI_OVER_2, LIBC_NAMESPACE::atan2f(neg_inf, neg_zero));
+ EXPECT_FP_EQ(PI_OVER_4, LIBC_NAMESPACE::atan2f(inf, inf));
+ EXPECT_FP_EQ(-PI_OVER_4, LIBC_NAMESPACE::atan2f(neg_inf, inf));
+ EXPECT_FP_EQ(THREE_PI_OVER_4, LIBC_NAMESPACE::atan2f(inf, neg_inf));
+ EXPECT_FP_EQ(-THREE_PI_OVER_4, LIBC_NAMESPACE::atan2f(neg_inf, neg_inf));
+
EXPECT_FP_EQ_WITH_EXCEPTION(aNaN, LIBC_NAMESPACE::atan2f(sNaN, sNaN),
FE_INVALID);
EXPECT_MATH_ERRNO(0);
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