[libc-commits] [libc] [llvm] [libc][math] Refactor hypotf16 to header-only shared math (PR #175438)

[Muhammad Bassiouni via libc-commits]

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@@ -0,0 +1,64 @@
+//===-- Generic implementation of hypotf16 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_MATH_HYPOTF16_H
+#define LLVM_LIBC_SRC___SUPPORT_MATH_HYPOTF16_H
+
+#include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/sqrt.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/optimization.h"
+
+namespace LIBC_NAMESPACE_DECL {
+namespace math {
+
+LIBC_INLINE float16 hypotf16(float16 x, float16 y) {
+  using FPBits = fputil::FPBits<float16>;
+
+  FPBits x_bits(x);
+  FPBits y_bits(y);
+
+  // Remove signs
+  x_bits.set_sign(Sign::POS);
+  y_bits.set_sign(Sign::POS);
+
+  // Handle special cases
+  // If either is NaN, return NaN
+  if (LIBC_UNLIKELY(x_bits.is_nan() || y_bits.is_nan())) {
+    return FPBits::quiet_nan().get_val();
+  }
+
+  // If either is infinity, return infinity
+  if (LIBC_UNLIKELY(x_bits.is_inf() || y_bits.is_inf())) {
+    return FPBits::inf().get_val();
+  }
+
+  // If either is zero, return the other
+  if (LIBC_UNLIKELY(x_bits.is_zero())) {
+    return y_bits.get_val();
+  }
+  if (LIBC_UNLIKELY(y_bits.is_zero())) {
+    return x_bits.get_val();
+  }
+
+  // For float16, we can promote to float32 for the computation
+  // to avoid overflow/underflow issues
+  float x_f32 = static_cast<float>(x);
+  float y_f32 = static_cast<float>(y);
+
+  // Compute hypot using the standard formula
+  float result_f32 = fputil::sqrt<float>(x_f32 * x_f32 + y_f32 * y_f32);
+
+  // Convert back to float16
+  return static_cast<float16>(result_f32);
+}
+
+} // namespace math
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_MATH_HYPOTF16_H
----------------
bassiounix wrote:

```suggestion
#endif // LLVM_LIBC_SRC___SUPPORT_MATH_HYPOTF16_H

```

https://github.com/llvm/llvm-project/pull/175438