[libc] Add sinpif16 function

libc/config/linux/x86_64/entrypoints.txt

@@ -573,7 +573,6 @@ set(TARGET_LIBM_ENTRYPOINTS
     libc.src.math.sinf
     libc.src.math.sinhf
     libc.src.math.sinpif
-    libc.src.math.sinpif16
     libc.src.math.sqrt
     libc.src.math.sqrtf
     libc.src.math.sqrtl
@@ -668,7 +667,8 @@ if(LIBC_TYPES_HAS_FLOAT16)
     libc.src.math.scalblnf16
     libc.src.math.scalbnf16
     libc.src.math.setpayloadf16
-    libc.src.math.setpayloadsigf16
+    libc.src.math.setpayloadsigf16 
+    libc.src.math.sinpif16
     libc.src.math.totalorderf16
     libc.src.math.totalordermagf16
     libc.src.math.truncf16

libc/docs/math/index.rst

@@ -342,7 +342,7 @@ Higher Math Functions
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | sinh      | |check|          |                 |                        |                      |                        | 7.12.5.5               | F.10.2.5                   |
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
-| sinpi     | |check|          |                 |                        |                      |                        | 7.12.4.13              | F.10.1.13                  |
+| sinpi     | |check|          |                 |                        |  |check|             |                        | 7.12.4.13              | F.10.1.13                  |
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+
 | sqrt      | |check|          | |check|         | |check|                |                      | |check|                | 7.12.7.10              | F.10.4.10                  |
 +-----------+------------------+-----------------+------------------------+----------------------+------------------------+------------------------+----------------------------+

libc/src/math/generic/sinpif16.cpp

@@ -74,10 +74,9 @@ LLVM_LIBC_FUNCTION(float16, sinpif16, (float16 x)) {
   // * pi/32) and cos(y * pi/32) are computed using degree-9 chebyshev
   // polynomials generated by Sollya.
 
-  if (LIBC_UNLIKELY(x_abs == 0U)) {
-    // For signed zeros
+  // For signed zeros
+  if (LIBC_UNLIKELY(x_abs == 0U))
     return x;
-  }
 
   // Numbers greater or equal to 2^10 are integers, or infinity, or NaN
   if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
@@ -101,8 +100,6 @@ LLVM_LIBC_FUNCTION(float16, sinpif16, (float16 x)) {
   float sin_k = SIN_K_PI_OVER_32[k & 63];
   float cos_k = SIN_K_PI_OVER_32[(k + 16) & 63];
 
-  float cosm1_y, sin_y;
-
   // Recall;
   // sin(x * pi/32) = sin((k + y) * pi/32)
   // 		    = sin(y * pi/32) * cos(k * pi/32) + cos(y * pi/32) * sin(k *
@@ -115,22 +112,22 @@ LLVM_LIBC_FUNCTION(float16, sinpif16, (float16 x)) {
   // Degree-6 minimax even polynomial for sin(y*pi/32)/y generated by Sollya
   // with:
   // > Q = fpminimax(sin(y*pi/32)/y, [|0, 2, 4, 6|], [|SG...|], [0, 0.5]);
-  sin_y = y * fputil::polyeval(ysq, 0x1.921fb6p-4f, -0x1.4aeabcp-13f,
-                               0x1.a03354p-21f, -0x1.ad02d2p-20f);
+  float sin_y = y * fputil::polyeval(ysq, 0x1.921fb6p-4f, -0x1.4aeabcp-13f,
+                                     0x1.a03354p-21f, -0x1.ad02d2p-20f);
 
   // Note that cosm1_y = cos(y*pi/32) - 1 = cos_y - 1
-  // Derivation:                                                  // sin(x * pi)
-  // = sin((k + y) * pi/32)                           //             = sin_y *
-  // cos_k + cos_y * sin_k                  //             = cos_k * sin_y +
-  // sin_k * (1 + cos_y - 1) Degree-6 minimax even polynomial for cos(y*pi/32)
-  // generated by Sollya with: > P = fpminimax(cos(y*pi/32), [|0, 2, 4, 6|],
-  // [|1, SG...|], [0, 0.5]);
-  cosm1_y = ysq * fputil::polyeval(ysq, -0x1.3bd3ccp-8f, 0x1.03a61ap-18f,
-                                   0x1.a6f7a2p-29f);
-
-  if (LIBC_UNLIKELY(sin_y == 0 && sin_k == 0)) {
+  // Derivation:
+  // sin(x * pi) = sin((k + y) * pi/32)
+  //             = sin_y * cos_k + cos_y * sin_k
+  //             = cos_k * sin_y + sin_k * (1 + cos_y - 1)
+  // Degree-6 minimax even polynomial for cos(y*pi/32)
+  // generated by Sollya with:
+  // > P = fpminimax(cos(y*pi/32), [|0, 2, 4, 6|],[|1, SG...|], [0, 0.5]);
+  float cosm1_y = ysq * fputil::polyeval(ysq, -0x1.3bd3ccp-8f, 0x1.03a61ap-18f,
+                                         0x1.a6f7a2p-29f);
+
+  if (LIBC_UNLIKELY(sin_y == 0 && sin_k == 0))
     return FPBits::zero(xbits.sign()).get_val();
-  }
 
   // Since, cosm1_y = cos_y - 1, therefore:
   // 	sin(x * pi) = cos_k * sin_y + sin_k + (cosm1_y * sin_k)

libc/test/src/math/sinpif16_test.cpp

@@ -1,5 +1,4 @@
-//===-- Exhaustive test for sinpif16
-//---------------------------------------===//
+//===-- Exhaustive test for sinpif16---------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.

libc/utils/MPFRWrapper/MPFRUtils.cpp

@@ -488,6 +488,7 @@ class MPFRNumber {
     (MPFR_VERSION_MAJOR == 4 && MPFR_VERSION_MINOR >= 2)
 
     mpfr_sinpi(result.value, value, mpfr_rounding);
+    return result;
 #else
     if (mpfr_integer_p(value)) {
       mpfr_set_si(result.value, 0, mpfr_rounding);