[libc-commits] [libc] [llvm] [libc][math] Fix signaling nan handling of hypot(f) and improve hypotf performance. (PR #99432)

[via libc-commits]

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@@ -6,66 +6,88 @@
 //
 //===----------------------------------------------------------------------===//
 #include "src/math/hypotf.h"
-#include "src/__support/FPUtil/BasicOperations.h"
+#include "src/__support/FPUtil/FEnvImpl.h"
 #include "src/__support/FPUtil/FPBits.h"
+#include "src/__support/FPUtil/double_double.h"
+#include "src/__support/FPUtil/multiply_add.h"
 #include "src/__support/FPUtil/sqrt.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
+#include "src/__support/macros/optimization.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
 LLVM_LIBC_FUNCTION(float, hypotf, (float x, float y)) {
   using DoubleBits = fputil::FPBits<double>;
   using FPBits = fputil::FPBits<float>;
 
-  FPBits x_bits(x), y_bits(y);
+  FPBits x_abs = FPBits(x).abs();
+  FPBits y_abs = FPBits(y).abs();
 
-  uint16_t x_exp = x_bits.get_biased_exponent();
-  uint16_t y_exp = y_bits.get_biased_exponent();
-  uint16_t exp_diff = (x_exp > y_exp) ? (x_exp - y_exp) : (y_exp - x_exp);
+  bool x_abs_larger = x_abs.uintval() >= y_abs.uintval();
 
-  if (exp_diff >= FPBits::FRACTION_LEN + 2) {
-    return fputil::abs(x) + fputil::abs(y);
-  }
+  FPBits a_bits = x_abs_larger ? x_abs : y_abs;
+  FPBits b_bits = x_abs_larger ? y_abs : x_abs;
 
-  double xd = static_cast<double>(x);
-  double yd = static_cast<double>(y);
+  uint32_t a_u = a_bits.uintval();
+  uint32_t b_u = b_bits.uintval();
 
-  // These squares are exact.
-  double x_sq = xd * xd;
-  double y_sq = yd * yd;
+  if (LIBC_UNLIKELY(a_u >= FPBits::EXP_MASK)) {
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lntue wrote:

Using `a_bits.is_inf_or_nan()` generates extra exponent bit masking instructions.

https://github.com/llvm/llvm-project/pull/99432