[libc][math][c23] Add hypotbf16 function (llvm#183460)

Sukumarsawant · web-flow · commit ad054822eb3b · 2026-03-13T10:11:33.000-04:00
This PR intends to add hypotbf16 higher math function for BFloat16 type
along with the tests.
diff --git a/libc/config/baremetal/aarch64/entrypoints.txt b/libc/config/baremetal/aarch64/entrypoints.txt
@@ -818,6 +818,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/baremetal/arm/entrypoints.txt b/libc/config/baremetal/arm/entrypoints.txt
@@ -829,6 +829,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/baremetal/riscv/entrypoints.txt b/libc/config/baremetal/riscv/entrypoints.txt
@@ -824,6 +824,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/darwin/aarch64/entrypoints.txt b/libc/config/darwin/aarch64/entrypoints.txt
@@ -640,6 +640,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/darwin/x86_64/entrypoints.txt b/libc/config/darwin/x86_64/entrypoints.txt
@@ -270,6 +270,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/gpu/amdgpu/entrypoints.txt b/libc/config/gpu/amdgpu/entrypoints.txt
@@ -657,6 +657,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/gpu/nvptx/entrypoints.txt b/libc/config/gpu/nvptx/entrypoints.txt
@@ -659,6 +659,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
@@ -897,6 +897,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/linux/arm/entrypoints.txt b/libc/config/linux/arm/entrypoints.txt
@@ -508,6 +508,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
@@ -918,6 +918,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
@@ -968,6 +968,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/config/windows/entrypoints.txt b/libc/config/windows/entrypoints.txt
@@ -354,6 +354,7 @@ list(APPEND TARGET_LIBM_ENTRYPOINTS
   libc.src.math.fromfpbf16
   libc.src.math.fromfpxbf16
   libc.src.math.getpayloadbf16
+  libc.src.math.hypotbf16
   libc.src.math.ilogbbf16
   libc.src.math.iscanonicalbf16
   libc.src.math.issignalingbf16
diff --git a/libc/docs/headers/math/index.rst b/libc/docs/headers/math/index.rst
@@ -315,7 +315,7 @@ Higher Math Functions
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
 | fsqrt     | N/A              | |check|         |  |check|               | N/A                  | |check|\*              |                        | 7.12.14.6              | F.10.11                    |
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
-| hypot     | |check|          | |check|         |                        | |check|              |                        |                        | 7.12.7.4               | F.10.4.4                   |
+| hypot     | |check|          | |check|         |                        | |check|              |                        | |check|                | 7.12.7.4               | F.10.4.4                   |
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
 | lgamma    |                  |                 |                        |                      |                        |                        | 7.12.8.3               | F.10.5.3                   |
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+------------------------+----------------------------+
diff --git a/libc/shared/math.h b/libc/shared/math.h
@@ -151,6 +151,7 @@
 #include "math/getpayloadf128.h"
 #include "math/getpayloadf16.h"
 #include "math/getpayloadl.h"
+#include "math/hypotbf16.h"
 #include "math/hypotf.h"
 #include "math/hypotf16.h"
 #include "math/ilogb.h"
diff --git a/libc/shared/math/hypotbf16.h b/libc/shared/math/hypotbf16.h
@@ -0,0 +1,26 @@
+//===-- Shared hypotbf16 function -------------------------------*- 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_SHARED_MATH_HYPOTBF16_H
+#define LLVM_LIBC_SHARED_MATH_HYPOTBF16_H
+
+#include "shared/libc_common.h"
+
+#include "src/__support/math/hypotbf16.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace shared {
+
+using math::hypotbf16;
+
+} // namespace shared
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SHARED_MATH_HYPOTBF16_H
diff --git a/libc/src/__support/math/CMakeLists.txt b/libc/src/__support/math/CMakeLists.txt
@@ -1986,6 +1986,17 @@ add_header_library(
     libc.src.__support.macros.optimization
 )
 
+add_header_library(
+  hypotbf16
+  HDRS
+    hypotbf16.h
+  DEPENDS
+    libc.src.__support.FPUtil.hypot
+    libc.src.__support.FPUtil.bfloat16
+    libc.src.__support.common
+    libc.src.__support.macros.config
+)
+
 add_header_library(
   hypotf16
   HDRS
diff --git a/libc/src/__support/math/hypotbf16.h b/libc/src/__support/math/hypotbf16.h
@@ -0,0 +1,29 @@
+//===-- Implementation header for hypotbf16 ---------------------*- 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___SUPPORT_MATH_HYPOTBF16_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_HYPOTBF16_H
+
+#include "src/__support/FPUtil/Hypot.h"
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+namespace math {
+
+LIBC_INLINE bfloat16 hypotbf16(bfloat16 x, bfloat16 y) {
+  return fputil::hypot<bfloat16>(x, y);
+}
+
+} // namespace math
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_HYPOTBF16_H
diff --git a/libc/src/math/CMakeLists.txt b/libc/src/math/CMakeLists.txt
@@ -347,6 +347,7 @@ add_math_entrypoint_object(getpayloadf128)
 add_math_entrypoint_object(getpayloadbf16)
 
 add_math_entrypoint_object(hypot)
+add_math_entrypoint_object(hypotbf16)
 add_math_entrypoint_object(hypotf)
 add_math_entrypoint_object(hypotf16)
 
diff --git a/libc/src/math/generic/CMakeLists.txt b/libc/src/math/generic/CMakeLists.txt
@@ -3031,6 +3031,16 @@ add_entrypoint_object(
     libc.src.__support.macros.config
 )
 
+add_entrypoint_object(
+  hypotbf16
+  SRCS
+    hypotbf16.cpp
+  HDRS
+    ../hypotbf16.h
+  DEPENDS
+    libc.src.__support.math.hypotbf16
+)
+
 add_entrypoint_object(
   hypotf
   SRCS
diff --git a/libc/src/math/generic/hypotbf16.cpp b/libc/src/math/generic/hypotbf16.cpp
@@ -0,0 +1,18 @@
+//===-- Implementation of hypotbf16 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/hypotbf16.h"
+#include "src/__support/math/hypotbf16.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(bfloat16, hypotbf16, (bfloat16 x, bfloat16 y)) {
+  return math::hypotbf16(x, y);
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/math/hypotbf16.h b/libc/src/math/hypotbf16.h
@@ -0,0 +1,21 @@
+//===-- Implementation header for hypotbf16 ---------------------*- 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_HYPOTBF16_H
+#define LLVM_LIBC_SRC_MATH_HYPOTBF16_H
+
+#include "src/__support/macros/config.h"
+#include "src/__support/macros/properties/types.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+bfloat16 hypotbf16(bfloat16 x, bfloat16 y);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_MATH_HYPOTBF16_H
diff --git a/libc/test/shared/CMakeLists.txt b/libc/test/shared/CMakeLists.txt
@@ -149,6 +149,7 @@ add_fp_unittest(
     libc.src.__support.math.getpayloadf16
     libc.src.__support.math.getpayloadl
     libc.src.__support.math.hypotf
+    libc.src.__support.math.hypotbf16
     libc.src.__support.math.hypotf16
     libc.src.__support.math.ilogb
     libc.src.__support.math.ilogbf
diff --git a/libc/test/shared/shared_math_test.cpp b/libc/test/shared/shared_math_test.cpp
@@ -437,6 +437,9 @@ TEST(LlvmLibcSharedMathTest, AllBFloat16) {
   EXPECT_FP_EQ(bfloat16(-1.0),
                LIBC_NAMESPACE::shared::getpayloadbf16(&getpayloadbf16_x));
 
+  EXPECT_FP_EQ(bfloat16(5.0),
+               LIBC_NAMESPACE::shared::hypotbf16(bfloat16(4.0), bfloat16(3.0)));
+
   bfloat16 setpayloadbf16_res = bfloat16(0.0);
   EXPECT_EQ(0, LIBC_NAMESPACE::shared::setpayloadbf16(&setpayloadbf16_res,
                                                       bfloat16(0.0)));
diff --git a/libc/test/src/math/CMakeLists.txt b/libc/test/src/math/CMakeLists.txt
@@ -1896,6 +1896,19 @@ add_fp_unittest(
     libc.src.__support.FPUtil.fp_bits
 )
 
+add_fp_unittest(
+  hypotbf16_test
+  NEED_MPFR
+  SUITE
+    libc-math-unittests
+  SRCS
+    hypotbf16_test.cpp
+  DEPENDS
+    libc.src.math.hypotbf16
+    libc.src.__support.FPUtil.fp_bits
+    libc.src.__support.FPUtil.bfloat16
+)
+
 add_fp_unittest(
   hypotf16_test
   NEED_MPFR
diff --git a/libc/test/src/math/exhaustive/CMakeLists.txt b/libc/test/src/math/exhaustive/CMakeLists.txt
@@ -376,6 +376,24 @@ add_fp_unittest(
     -lpthread
 )
 
+add_fp_unittest(
+  hypotbf16_test
+  NO_RUN_POSTBUILD
+  NEED_MPFR
+  SUITE
+    libc_math_exhaustive_tests
+  SRCS
+    hypotbf16_test.cpp
+  COMPILE_OPTIONS
+    ${libc_opt_high_flag}
+  DEPENDS
+    .exhaustive_test
+    libc.src.math.hypotbf16
+    libc.src.__support.FPUtil.bfloat16
+  LINK_LIBRARIES
+    -lpthread
+)
+
 add_fp_unittest(
   hypotf_test
   NO_RUN_POSTBUILD
diff --git a/libc/test/src/math/exhaustive/hypotbf16_test.cpp b/libc/test/src/math/exhaustive/hypotbf16_test.cpp
@@ -0,0 +1,72 @@
+//===-- Exhaustive test for hypotbf16 -------------------------------------===//
+//
+// 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 "exhaustive_test.h"
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/Hypot.h"
+#include "src/__support/FPUtil/bfloat16.h"
+#include "src/math/hypotbf16.h"
+#include "test/UnitTest/FPMatcher.h"
+#include "utils/MPFRWrapper/MPFRUtils.h"
+
+namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
+
+struct Hypotbf16Checker : public virtual LIBC_NAMESPACE::testing::Test {
+  using FloatType = bfloat16;
+  using FPBits = LIBC_NAMESPACE::fputil::FPBits<bfloat16>;
+  using StorageType = typename FPBits::StorageType;
+
+  uint64_t check(uint16_t x_start, uint16_t x_stop, uint16_t y_start,
+                 uint16_t y_stop, mpfr::RoundingMode rounding) {
+    mpfr::ForceRoundingMode r(rounding);
+    if (!r.success)
+      return true;
+    uint16_t xbits = x_start;
+    uint64_t failed = 0;
+    do {
+      bfloat16 x = FPBits(xbits).get_val();
+      uint16_t ybits = y_start;
+      do {
+        bfloat16 y = FPBits(ybits).get_val();
+        mpfr::BinaryInput<bfloat16> input{x, y};
+        bool correct = TEST_MPFR_MATCH_ROUNDING_SILENTLY(
+            mpfr::Operation::Hypot, input, LIBC_NAMESPACE::hypotbf16(x, y), 0.5,
+            rounding);
+        failed += (!correct);
+      } while (ybits++ < y_stop);
+    } while (xbits++ < x_stop);
+    return failed;
+  }
+};
+
+using LlvmLibcHypotBf16ExhaustiveTest =
+    LlvmLibcExhaustiveMathTest<Hypotbf16Checker, 1 << 2>;
+
+// range: [0, inf]
+static constexpr uint16_t POS_START = 0x0000U;
+static constexpr uint16_t POS_STOP = 0x7f80U;
+
+// range: [-0, -inf]
+static constexpr uint16_t NEG_START = 0x8000U;
+static constexpr uint16_t NEG_STOP = 0xff80U;
+
+TEST_F(LlvmLibcHypotBf16ExhaustiveTest, PositiveRange) {
+  test_full_range_all_roundings(POS_START, POS_STOP, POS_START, POS_STOP);
+}
+
+TEST_F(LlvmLibcHypotBf16ExhaustiveTest, NegativeRange) {
+  test_full_range_all_roundings(NEG_START, NEG_STOP, NEG_START, NEG_STOP);
+}
+
+TEST_F(LlvmLibcHypotBf16ExhaustiveTest, PositiveNegativeRange) {
+  test_full_range_all_roundings(POS_START, POS_STOP, NEG_START, NEG_STOP);
+}
+
+TEST_F(LlvmLibcHypotBf16ExhaustiveTest, NegativePositiveRange) {
+  test_full_range_all_roundings(NEG_START, NEG_STOP, POS_START, POS_STOP);
+}
diff --git a/libc/test/src/math/hypotbf16_test.cpp b/libc/test/src/math/hypotbf16_test.cpp
diff --git a/libc/test/src/math/smoke/CMakeLists.txt b/libc/test/src/math/smoke/CMakeLists.txt
diff --git a/libc/test/src/math/smoke/HypotTest.h b/libc/test/src/math/smoke/HypotTest.h
diff --git a/libc/test/src/math/smoke/hypotbf16_test.cpp b/libc/test/src/math/smoke/hypotbf16_test.cpp
diff --git a/utils/bazel/llvm-project-overlay/libc/BUILD.bazel b/utils/bazel/llvm-project-overlay/libc/BUILD.bazel
