[libc-commits] [libc] [libc] Add cospif16 function (PR #113001)

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<!--LLVM CODE FORMAT COMMENT: {clang-format}-->


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``````````bash
git-clang-format --diff 9065b759ae73fac5edc01fc6c3878642bedfca5d f0e8bf98b5603a743aa78d88d9df8cd4e345f579 --extensions h,cpp -- libc/src/math/cospif16.h libc/src/math/generic/cospif16.cpp libc/test/src/math/cospif16_test.cpp libc/test/src/math/smoke/cospif16_test.cpp libc/src/math/generic/exp10f16.cpp
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View the diff from clang-format here.
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``````````diff
diff --git a/libc/src/math/generic/cospif16.cpp b/libc/src/math/generic/cospif16.cpp
index 779aab781b..90deb4a77d 100644
--- a/libc/src/math/generic/cospif16.cpp
+++ b/libc/src/math/generic/cospif16.cpp
@@ -75,28 +75,28 @@ LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) {
   // polynomials generated by Sollya.
 
   // For signed zeros
-  if (LIBC_UNLIKELY(x_abs == 0U)) return fputil::cast<float16>(1.0f);
+  if (LIBC_UNLIKELY(x_abs == 0U))
+    return fputil::cast<float16>(1.0f);
 
   // Numbers greater or equal to 2^10 are integers, or infinity, or NaN
   if (LIBC_UNLIKELY(x_abs >= 0x6400)) {
     if (LIBC_UNLIKELY(x_abs <= 0x67FF)) {
-      return fputil::cast<float16>((x_abs & 0x1) ? -1.0f : 1.0f); 
+      return fputil::cast<float16>((x_abs & 0x1) ? -1.0f : 1.0f);
     }
-     
+
     // Check for NaN or infintiy values
     if (LIBC_UNLIKELY(x_abs >= 0x7c00)) {
       // If value is equal to infinity
       if (x_abs == 0x7c00) {
         fputil::set_errno_if_required(EDOM);
-	fputil::raise_except_if_required(FE_INVALID);
+        fputil::raise_except_if_required(FE_INVALID);
       }
 
       return x + FPBits::quiet_nan().get_val();
     }
-    
-    return fputil::cast<float16>(1.0f); 
+
+    return fputil::cast<float16>(1.0f);
   }
-  
 
   float f32 = x;
   float y;
@@ -107,8 +107,8 @@ LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) {
 
   // Recall;
   // cos(x * pi/32) = cos((k + y) * pi/32)
-  // 		    = cos(y * pi/32) * cos(k * pi/32) 
-  // 		      - sin(y * pi/32) * sin(k * pi/32) 
+  // 		    = cos(y * pi/32) * cos(k * pi/32)
+  // 		      - sin(y * pi/32) * sin(k * pi/32)
   // Recall, after range reduction, -0.5 <= y <= 0.5. For very small
   // values of y, calculating sin(y * p/32) can be inaccurate. Generating a
   // polynomial for sin(y * p/32)/y instead significantly reduces the relative
@@ -116,7 +116,7 @@ LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) {
   float ysq = y * y;
 
   // Degree-6 minimax even polynomial for sin(y*pi/32)/y generated by Sollya
-  // with: 
+  // with:
   // > Q = fpminimax(sin(y*pi/32)/y, [|0, 2, 4, 6|], [|SG...|], [0, 0.5]);
   float sin_y = y * fputil::polyeval(ysq, 0x1.921fb6p-4f, -0x1.4aeabcp-13f,
                                      0x1.a03354p-21f, -0x1.ad02d2p-20f);
@@ -136,6 +136,7 @@ LLVM_LIBC_FUNCTION(float16, cospif16, (float16 x)) {
 
   // Since, cosm1_y = cos_y - 1, therefore:
   // 	cos(x * pi) = cos_k(cosm1_y) + cos_k - sin_k * sin_y
-  return fputil::cast<float16>(fputil::multiply_add(cos_k, cosm1_y, fputil::multiply_add(-sin_k, sin_y, cos_k)));
+  return fputil::cast<float16>(fputil::multiply_add(
+      cos_k, cosm1_y, fputil::multiply_add(-sin_k, sin_y, cos_k)));
 }
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/test/src/math/cospif16_test.cpp b/libc/test/src/math/cospif16_test.cpp
index 1ba70c31cc..2c61086ef8 100644
--- a/libc/test/src/math/cospif16_test.cpp
+++ b/libc/test/src/math/cospif16_test.cpp
@@ -26,13 +26,15 @@ static constexpr uint16_t NEG_STOP = 0xfc00U;
 TEST_F(LlvmLibcCospif16Test, PositiveRange) {
   for (uint16_t v = POS_START; v <= POS_STOP; ++v) {
     float16 x = FPBits(v).get_val();
-    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Cospi, x, LIBC_NAMESPACE::cospif16(x), 0.5);
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Cospi, x,
+                                   LIBC_NAMESPACE::cospif16(x), 0.5);
   }
 }
 
 TEST_F(LlvmLibcCospif16Test, NegativeRange) {
   for (uint16_t v = NEG_START; v <= NEG_STOP; ++v) {
     float16 x = FPBits(v).get_val();
-    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Cospi, x, LIBC_NAMESPACE::cospif16(x), 0.5);
+    EXPECT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Cospi, x,
+                                   LIBC_NAMESPACE::cospif16(x), 0.5);
   }
 }

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https://github.com/llvm/llvm-project/pull/113001