[libc-commits] [libc] bb3419b - [libc] Fix Atan2f128 and add tests for all versions (#215023)
via libc-commits
libc-commits at lists.llvm.org
Sat Aug 8 15:20:01 PDT 2026
Author: Zorojuro
Date: 2026-08-08T18:19:56-04:00
New Revision: bb3419bc0de6f04753984330e27b47b894b081e4
URL: https://github.com/llvm/llvm-project/commit/bb3419bc0de6f04753984330e27b47b894b081e4
DIFF: https://github.com/llvm/llvm-project/commit/bb3419bc0de6f04753984330e27b47b894b081e4.diff
LOG: [libc] Fix Atan2f128 and add tests for all versions (#215023)
It fixes the THREE_PI_OVER_4 value in atan2f128 and adds a small smoke
test against the failure.
The result or comparison value is directly taken from the failure while
comparing with core math :
```CPP
FAIL x=inf y=-inf ref=0x1.2d97c7f3321d234f272993d1414ap+1 z=0x1.2d97c7f3321d234f272993d1414ap-1
```
Additionally it adds some more smoke tests for all atan2 versions.
Added:
Modified:
libc/src/__support/math/atan2f128.h
libc/test/src/math/smoke/atan2_test.cpp
libc/test/src/math/smoke/atan2f128_test.cpp
libc/test/src/math/smoke/atan2f16_test.cpp
libc/test/src/math/smoke/atan2f_test.cpp
Removed:
################################################################################
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/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 28b15ae71cac8..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));
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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