From bb69a8db5da21f3c6b289d010eaa64e757387dca Mon Sep 17 00:00:00 2001
From: Antonio Sanchez <cantonios@google.com>
Date: Thu, 12 Nov 2020 13:12:00 -0800
Subject: Explicit casts of S -> std::complex<T>

When calling `internal::cast<S, std::complex<T>>(x)`, clang often
generates an implicit conversion warning due to an implicit cast
from type `S` to `T`.  This currently affects the following tests:
- `basicstuff`
- `bfloat16_float`
- `cxx11_tensor_casts`

The implicit cast leads to widening/narrowing float conversions.
Widening warnings only seem to be generated by clang (`-Wdouble-promotion`).

To eliminate the warning, we explicitly cast the real-component first
from `S` to `T`.  We also adjust tests to use `internal::cast` instead
of `static_cast` when a complex type may be involved.
---
 test/basicstuff.cpp     | 33 ++-------------------------------
 test/bfloat16_float.cpp | 16 ++++++++--------
 2 files changed, 10 insertions(+), 39 deletions(-)

(limited to 'test')

diff --git a/test/basicstuff.cpp b/test/basicstuff.cpp
index f9044a27a..4ca607c82 100644
--- a/test/basicstuff.cpp
+++ b/test/basicstuff.cpp
@@ -195,11 +195,8 @@ template<typename MatrixType> void basicStuffComplex(const MatrixType& m)
   VERIFY(!static_cast<const MatrixType&>(cm).imag().isZero());
 }
 
-template<typename SrcScalar, typename TgtScalar, bool SrcIsHalfOrBF16 = (internal::is_same<SrcScalar, half>::value || internal::is_same<SrcScalar, bfloat16>::value)> struct casting_test;
-
-
 template<typename SrcScalar, typename TgtScalar>
-struct casting_test<SrcScalar, TgtScalar, false> {
+struct casting_test {
   static void run() {
     Matrix<SrcScalar,4,4> m;
     for (int i=0; i<m.rows(); ++i) {
@@ -210,33 +207,7 @@ struct casting_test<SrcScalar, TgtScalar, false> {
     Matrix<TgtScalar,4,4> n = m.template cast<TgtScalar>();
     for (int i=0; i<m.rows(); ++i) {
       for (int j=0; j<m.cols(); ++j) {
-        VERIFY_IS_APPROX(n(i, j), static_cast<TgtScalar>(m(i, j)));
-      }
-    }
-  }
-};
-
-template<typename SrcScalar, typename TgtScalar>
-struct casting_test<SrcScalar, TgtScalar, true> {
-  static void run() {
-    casting_test<SrcScalar, TgtScalar, false>::run();
-  }
-};
-
-template<typename SrcScalar, typename RealScalar>
-struct casting_test<SrcScalar, std::complex<RealScalar>, true> {
-  static void run() {
-    typedef std::complex<RealScalar> TgtScalar;
-    Matrix<SrcScalar,4,4> m;
-    for (int i=0; i<m.rows(); ++i) {
-      for (int j=0; j<m.cols(); ++j) {
-        m(i, j) = internal::random_without_cast_overflow<SrcScalar, TgtScalar>::value();
-      }
-    }
-    Matrix<TgtScalar,4,4> n = m.template cast<TgtScalar>();
-    for (int i=0; i<m.rows(); ++i) {
-      for (int j=0; j<m.cols(); ++j) {
-        VERIFY_IS_APPROX(n(i, j), static_cast<TgtScalar>(static_cast<RealScalar>(m(i, j))));
+        VERIFY_IS_APPROX(n(i, j), (internal::cast<SrcScalar,TgtScalar>(m(i, j))));
       }
     }
   }
diff --git a/test/bfloat16_float.cpp b/test/bfloat16_float.cpp
index 79c868e84..09df2b2f2 100644
--- a/test/bfloat16_float.cpp
+++ b/test/bfloat16_float.cpp
@@ -44,14 +44,14 @@ void test_truncate(float input, float expected_truncation, float expected_roundi
 template<typename T>
  void test_roundtrip() {
   // Representable T round trip via bfloat16
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(-std::numeric_limits<T>::infinity())), -std::numeric_limits<T>::infinity());
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(std::numeric_limits<T>::infinity())), std::numeric_limits<T>::infinity());
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(T(-1.0))), T(-1.0));
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(T(-0.5))), T(-0.5));
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(T(-0.0))), T(-0.0));
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(T(1.0))), T(1.0));
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(T(0.5))), T(0.5));
-  VERIFY_IS_EQUAL(static_cast<T>(static_cast<bfloat16>(T(0.0))), T(0.0));
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(-std::numeric_limits<T>::infinity()))), -std::numeric_limits<T>::infinity());
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(std::numeric_limits<T>::infinity()))), std::numeric_limits<T>::infinity());
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(T(-1.0)))), T(-1.0));
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(T(-0.5)))), T(-0.5));
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(T(-0.0)))), T(-0.0));
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(T(1.0)))), T(1.0));
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(T(0.5)))), T(0.5));
+  VERIFY_IS_EQUAL((internal::cast<bfloat16,T>(internal::cast<T,bfloat16>(T(0.0)))), T(0.0));
 }
 
 void test_conversion()
-- 
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