Addressed the feedback:

- Moved comments about polynomial in line 55 to remove redundancy
- Renamed constexpr array with capital letters
- Added file that was missed in initial commit
- Ran clang-format on files

Author: amemov

libc/src/math/generic/acospif16.cpp

@@ -51,7 +51,11 @@ LLVM_LIBC_FUNCTION(float16, acospif16, (float16 x)) {
 
   float xf = x;
   float xsq = xf * xf;
-  constexpr float poly_coeffs[5] = {0x1.45f308p-2f, 0x1.b2900cp-5f,
+
+  // Degree-6 minimax polynomial coefficients of asin(x) generated by Sollya
+  // with: > P = fpminimax(asin(x)/(pi * x), [|0, 2, 4, 6, 8|], [|SG...|], [0,
+  // 0.5]);
+  constexpr float POLY_COEFFS[5] = {0x1.45f308p-2f, 0x1.b2900cp-5f,
                                     0x1.897e36p-6f, 0x1.9efafcp-7f,
                                     0x1.06d884p-6f};
   // |x| <= 0x1p-1, |x| <= 0.5
@@ -62,12 +66,9 @@ LLVM_LIBC_FUNCTION(float16, acospif16, (float16 x)) {
 
     // Note that: acos(x) = pi/2 + asin(-x) = pi/2 - asin(x), then
     //            acospi(x) = 0.5 - asin(x)/pi
-    // Degree-6 minimax polynomial of asin(x) generated by Sollya with:
-    // > P = fpminimax(asin(x)/(pi * x), [|0, 2, 4, 6, 8|], [|SG...|], [0,
-    // 0.5]);
     float interm =
-        fputil::polyeval(xsq, poly_coeffs[0], poly_coeffs[1], poly_coeffs[2],
-                         poly_coeffs[3], poly_coeffs[4]);
+        fputil::polyeval(xsq, POLY_COEFFS[0], POLY_COEFFS[1], POLY_COEFFS[2],
+                         POLY_COEFFS[3], POLY_COEFFS[4]);
 
     return fputil::cast<float16>(fputil::multiply_add(-xf, interm, 0.5f));
   }
@@ -118,11 +119,9 @@ LLVM_LIBC_FUNCTION(float16, acospif16, (float16 x)) {
   float u = fputil::multiply_add(-0.5f, xf_abs, 0.5f);
   float sqrt_u = fputil::sqrt<float>(u);
 
-  // Degree-6 minimax polynomial of asin(x) generated by Sollya with:
-  // > P = fpminimax(asin(x)/(pi * x), [|0, 2, 4, 6, 8|], [|SG...|], [0, 0.5]);
   float asin_sqrt_u =
-      sqrt_u * fputil::polyeval(u, poly_coeffs[0], poly_coeffs[1],
-                                poly_coeffs[2], poly_coeffs[3], poly_coeffs[4]);
+      sqrt_u * fputil::polyeval(u, POLY_COEFFS[0], POLY_COEFFS[1],
+                                POLY_COEFFS[2], POLY_COEFFS[3], POLY_COEFFS[4]);
 
   // Same as acos(x), but devided the expression with pi
   return fputil::cast<float16>(

libc/utils/MPFRWrapper/MPCommon.h

@@ -180,6 +180,7 @@ class MPFRNumber {
   bool is_nan() const;
   MPFRNumber abs() const;
   MPFRNumber acos() const;
+  MPFRNumber acospi() const;
   MPFRNumber acosh() const;
   MPFRNumber add(const MPFRNumber &b) const;
   MPFRNumber asin() const;

libc/utils/MPFRWrapper/MPFRUtils.cpp

@@ -33,7 +33,7 @@ unary_operation(Operation op, InputType input, unsigned int precision,
   case Operation::Acosh:
     return mpfrInput.acosh();
   case Operation::Acospi:
-    return mpfrInput.acospi();  
+    return mpfrInput.acospi();
   case Operation::Asin:
     return mpfrInput.asin();
   case Operation::Asinh: