changes post review

Author: wldfngrs

libc/src/math/atanf16.h

@@ -1,8 +1,9 @@
 //===-- Implementation header for atanf16 -----------------------*- 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.     //
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception.
+//
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_LIBC_SRC_MATH_ATANF16_H

libc/src/math/generic/atanf16.cpp

@@ -78,20 +78,24 @@ LLVM_LIBC_FUNCTION(float16, atanf16, (float16 x)) {
     }
 
     // Degree-14 minimax odd polynomial of atan(x) generated by Sollya with:
-    // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|], [0,
-    // 1]);
+    // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|],
+    // [0, 1]);
     float result = fputil::polyeval(
         xsq, 0x1.fffffcp-1f, -0x1.55519ep-2f, 0x1.98f6a8p-3f, -0x1.1f0a92p-3f,
         0x1.95b654p-4f, -0x1.e65492p-5f, 0x1.8c0c36p-6f, -0x1.32316ep-8f);
     return fputil::cast<float16>(xf * result);
   }
 
   // If |x| > 1
-  // y = atan(x)
-  // y = atan(|x|) = pi/2 - atan(1/|x|)
+  // y = atan(x) = sign(x) * atan(|x|)
+  // atan(|x|) = pi/2 - atan(1/|x|)
   // Recall, 1/|x| < 1
   float x_inv_sq = 1 / xsq;
   float x_inv = fputil::sqrt<float>(x_inv_sq);
+
+  // Degree-14 minimax odd polynomial of atan(x) generated by Sollya with:
+  // > P = fpminimax(atan(x)/x, [|0, 2, 4, 6, 8, 10, 12, 14|], [|SG...|],
+  // [0, 1]);
   float interm =
       fputil::polyeval(x_inv_sq, 0x1.fffffcp-1f, -0x1.55519ep-2f,
                        0x1.98f6a8p-3f, -0x1.1f0a92p-3f, 0x1.95b654p-4f,

libc/test/src/math/atanf16_test.cpp

@@ -1,3 +1,11 @@
+//===-- Exhaustive test for atanf16 ---------------------------------------===//
+//
+// 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/atanf16.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"

libc/test/src/math/smoke/atanf16_test.cpp

@@ -1,6 +1,5 @@
 //===-- Unittests for atanf16 ---------------------------------------------===//
 //
-//
 // 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.