[libc-commits] [libc] [libc][math] Implement correctly rounded double precision tan (PR #97489)

[via libc-commits]

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@@ -6,27 +6,116 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/__support/FPUtil/FPBits.h"
 #include "src/math/tan.h"
 #include "test/UnitTest/FPMatcher.h"
 #include "test/UnitTest/Test.h"
 #include "utils/MPFRWrapper/MPFRUtils.h"
 
-#include "hdr/math_macros.h"
-
 using LlvmLibcTanTest = LIBC_NAMESPACE::testing::FPTest<double>;
 
 namespace mpfr = LIBC_NAMESPACE::testing::mpfr;
 
-TEST_F(LlvmLibcTanTest, Range) {
-  static constexpr double _2pi = 6.283185307179586;
-  constexpr StorageType COUNT = 100'000;
-  constexpr StorageType STEP = STORAGE_MAX / COUNT;
-  for (StorageType i = 0, v = 0; i <= COUNT; ++i, v += STEP) {
-    double x = FPBits(v).get_val();
-    // TODO: Expand the range of testing after range reduction is implemented.
-    if (isnan(x) || isinf(x) || x > _2pi || x < -_2pi)
-      continue;
-
-    ASSERT_MPFR_MATCH(mpfr::Operation::Tan, x, LIBC_NAMESPACE::tan(x), 1.0);
+using LIBC_NAMESPACE::testing::tlog;
+
+TEST_F(LlvmLibcTanTest, TrickyInputs) {
+  constexpr double INPUTS[] = {
+      0x1.d130383d17321p-27,   0x1.8000000000009p-23,  0x1.8000000000024p-22,
+      0x1.800000000009p-21,    0x1.20000000000f3p-20,  0x1.800000000024p-20,
+      0x1.e0000000001c2p-20,   0x1.0da8cc189b47dp-10,  0x1.00a33764a0a83p-7,
+      0x1.911a18779813fp-7,    0x1.940c877fb7dacp-7,   0x1.f42fb19b5b9b2p-6,
+      0x1.0285070f9f1bcp-5,    0x1.6ca9ef729af76p-1,   0x1.23f40dccdef72p+0,
+      0x1.43cf16358c9d7p+0,    0x1.addf3b9722265p+0,   0x1.ae78d360afa15p+0,
+      0x1.fe81868fc47fep+1,    0x1.e31b55306f22cp+2,   0x1.e639103a05997p+2,
+      0x1.f7898d5a756ddp+2,    0x1.1685973506319p+3,   0x1.5f09cad750ab1p+3,
+      0x1.aaf85537ea4c7p+3,    0x1.4f2b874135d27p+4,   0x1.13114266f9764p+4,
+      0x1.a211877de55dbp+4,    0x1.a5eece87e8606p+4,   0x1.a65d441ea6dcep+4,
+      0x1.1ffb509f3db15p+5,    0x1.2345d1e090529p+5,   0x1.c96e28eb679f8p+5,
+      0x1.da1838053b866p+5,    0x1.be886d9c2324dp+6,   0x1.ab514bfc61c76p+7,
+      0x1.14823229799c2p+7,    0x1.48ff1782ca91dp+8,   0x1.dcbfda0c7559ep+8,
+      0x1.dcbfda0c7559ep+8,    0x1.2e566149bf5fdp+9,   0x1.cb996c60f437ep+9,
+      0x1.119471e9216cdp+10,   0x1.ae945054939c2p+10,  0x1.fffffffffdb6p+24,
+      0x1.fd4da4ef37075p+29,   0x1.55202aefde314p+31,  0x1.b951f1572eba5p+31,
+      0x1.76e86a7485a46p59,    0x1.7776c2343ba4ep+101, 0x1.85fc0f04c0128p+101,
+      0x1.678309fa50d58p+110,  0x1.524489232dc4ap+178, 0x1.fffffffffef4ep+199,
+      0x1.6deb37da81129p+205,  0x1.3eec5912ea7cdp+331, 0x1.08087e9aad90bp+887,
+      0x1.6ac5b262ca1ffp+843,  0x1.8bb5847d49973p+845, 0x1.6ac5b262ca1ffp+849,
+      0x1.f08b14e1c4d0fp+890,  0x1.2b5fe88a9d8d5p+903, 0x1.a880417b7b119p+1023,
+      0x1.f6d7518808571p+1023,
+  };
+  constexpr int N = sizeof(INPUTS) / sizeof(INPUTS[0]);
+
+  for (int i = 0; i < N; ++i) {
+    double x = INPUTS[i];
+    ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Tan, x,
+                                   LIBC_NAMESPACE::tan(x), 0.5);
+    ASSERT_MPFR_MATCH_ALL_ROUNDING(mpfr::Operation::Tan, -x,
+                                   LIBC_NAMESPACE::tan(-x), 0.5);
   }
 }
+
+TEST_F(LlvmLibcTanTest, InDoubleRange) {
+  constexpr uint64_t COUNT = 1'234'51;
+  uint64_t START = LIBC_NAMESPACE::fputil::FPBits<double>(0x1.0p-50).uintval();
+  uint64_t STOP = LIBC_NAMESPACE::fputil::FPBits<double>(0x1.0p200).uintval();
+  uint64_t STEP = (STOP - START) / COUNT;
+
+  auto test = [&](mpfr::RoundingMode rounding_mode) {
+    mpfr::ForceRoundingMode __r(rounding_mode);
----------------
lntue wrote:

Updated the name.

https://github.com/llvm/llvm-project/pull/97489