[SYCL][ESIMD] fix atan2 implementation to work correctly with fast-ma…

…th switch (#13186)
intel · Apr 24, 2024 · 1f72a47 · 1f72a47
1 parent 425dbd7
commit 1f72a47
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Showing 2 changed files with 12 additions and 15 deletions.
diff --git a/sycl/include/sycl/ext/intel/experimental/esimd/math.hpp b/sycl/include/sycl/ext/intel/experimental/esimd/math.hpp
@@ -1445,22 +1445,22 @@ template <> ESIMD_INLINE float atan2_fast(float y, float x) {
 template <int N>
 ESIMD_INLINE __ESIMD_NS::simd<float, N> atan2(__ESIMD_NS::simd<float, N> y,
                                               __ESIMD_NS::simd<float, N> x) {
-  __ESIMD_NS::simd<float, N> v_distance;
   __ESIMD_NS::simd<float, N> atan2;
   __ESIMD_NS::simd_mask<N> mask;
+  __ESIMD_NS::simd<float, N> atan = esimd::atan(y / x);
 
   constexpr float CONST_DBL_EPSILON = 0.00001f;
 
-  mask = (x < -CONST_DBL_EPSILON && y < CONST_DBL_EPSILON && y >= 0.f);
-  atan2.merge(float(detail::__ESIMD_CONST_PI), 0.f, mask);
-  mask = (x < -CONST_DBL_EPSILON && y > -CONST_DBL_EPSILON && y < 0);
-  atan2.merge(float(-detail::__ESIMD_CONST_PI), mask);
-  mask = (x < CONST_DBL_EPSILON && __ESIMD_NS::abs(y) > CONST_DBL_EPSILON);
-  v_distance = __ESIMD_NS::sqrt(x * x + y * y);
-  atan2.merge(2.0f * esimd::atan((v_distance - x) / y), mask);
-
-  mask = (x > 0.f);
-  atan2.merge(2.0f * esimd::atan(y / (v_distance + x)), mask);
+  mask = (__ESIMD_NS::abs(x) < CONST_DBL_EPSILON && y < -CONST_DBL_EPSILON);
+  atan2.merge(float(-detail::__ESIMD_CONST_PI) / 2.f, 0.f, mask);
+  mask = (__ESIMD_NS::abs(x) < CONST_DBL_EPSILON && y > CONST_DBL_EPSILON);
+  atan2.merge(float(detail::__ESIMD_CONST_PI) / 2.f, mask);
+  mask = (x < -CONST_DBL_EPSILON && y < -CONST_DBL_EPSILON);
+  atan2.merge(atan - float(detail::__ESIMD_CONST_PI), mask);
+  mask = (x < -CONST_DBL_EPSILON && y >= -CONST_DBL_EPSILON);
+  atan2.merge(atan + float(detail::__ESIMD_CONST_PI), mask);
+  mask = (x > CONST_DBL_EPSILON);
+  atan2.merge(atan, mask);
 
   return atan2;
 }

diff --git a/sycl/test-e2e/ESIMD/regression/math_const_fix_test.cpp b/sycl/test-e2e/ESIMD/regression/math_const_fix_test.cpp
@@ -1,7 +1,4 @@
-// TODO: remove fno-fast-math option once the issue is investigated and the test
-// is fixed.
-// DEFINE: %{mathflags} = %if cl_options %{/clang:-fno-fast-math%} %else %{-fno-fast-math%}
-// RUN: %{build} %{mathflags} -o %t.out
+// RUN: %{build} -o %t.out
 // RUN: %{run} %t.out
 //==- math_const_fix_test.cpp - Test to verify math functions correctness-==//
 //