[libc-commits] [libc] [libc][math][c23] Add tanf16 function (PR #121018)

[via libc-commits]

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@@ -63,10 +63,11 @@ LIBC_INLINE int32_t range_reduction_sincospif16(float x, float &y) {
 // further intermediate computation.
 LIBC_INLINE int32_t range_reduction_sincosf16(float x, float &y) {
   double prod = x * 0x1.45f306dc9c883p3;
-  double kf = fputil::nearest_integer(prod);
-  y = static_cast<float>(prod - kf);
+  double kd = fputil::nearest_integer(prod);
 
-  return static_cast<int32_t>(kf);
+  y = static_cast<float>(prod - kd);
+
+  return static_cast<int32_t>(kd);
 }
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overmighty wrote:

Since you're already fixing a minor naming issue here, could you also introduce a variable for 32/pi instead of copy-pasting it in the comment above and explaining it there? I think something like this would be more readable:

 ```cpp
LIBC_INLINE int32_t range_reduction_sincosf16(float x, float &y) {
  // Generated by Sollya with:
  // > D(32/pi);
  constexpr double THIRTYTWO_OVER_PI = 0x1.45f306dc9c883p+3;

  double prod = x * THIRTYTWO_OVER_PI;
  double kd = fputil::nearest_integer(prod);
  y = static_cast<float>(prod - kd);

  return static_cast<int32_t>(kd);
}
```

https://github.com/llvm/llvm-project/pull/121018