Fix (u)int64_t->float conversion on arm

Eigen/src/Core/arch/NEON/TypeCasting.h

@@ -1111,11 +1111,11 @@ struct type_casting_traits<numext::int64_t, float> {
 };
 template <>
 EIGEN_STRONG_INLINE Packet4f pcast<Packet2l, Packet4f>(const Packet2l& a, const Packet2l& b) {
-  return vcvtq_f32_s32(vcombine_s32(vmovn_s64(a), vmovn_s64(b)));
+  return vcombine_f32(vcvt_f32_f64(vcvtq_f64_s64(a)), vcvt_f32_f64(vcvtq_f64_s64(b)));
 }
 template <>
 EIGEN_STRONG_INLINE Packet2f pcast<Packet2l, Packet2f>(const Packet2l& a) {
-  return vcvt_f32_s32(vmovn_s64(a));
+  return vcvt_f32_f64(vcvtq_f64_s64(a));
 }
 
 
@@ -1233,11 +1233,11 @@ struct type_casting_traits<numext::uint64_t, float> {
 };
 template <>
 EIGEN_STRONG_INLINE Packet4f pcast<Packet2ul, Packet4f>(const Packet2ul& a, const Packet2ul& b) {
-  return vcvtq_f32_u32(vcombine_u32(vmovn_u64(a), vmovn_u64(b)));
+  return vcombine_f32(vcvt_f32_f64(vcvtq_f64_u64(a)), vcvt_f32_f64(vcvtq_f64_u64(b)));
 }
 template <>
 EIGEN_STRONG_INLINE Packet2f pcast<Packet2ul, Packet2f>(const Packet2ul& a) {
-  return vcvt_f32_u32(vmovn_u64(a));
+  return vcvt_f32_f64(vcvtq_f64_u64(a));
 }
 
 

test/CMakeLists.txt

@@ -182,6 +182,7 @@ ei_add_test(first_aligned)
 ei_add_test(type_alias)
 ei_add_test(nullary)
 ei_add_test(mixingtypes)
+ei_add_test(float_conversion)
 ei_add_test(io)
 ei_add_test(packetmath "-DEIGEN_FAST_MATH=1")
 ei_add_test(vectorization_logic)

test/float_conversion.cpp

@@ -0,0 +1,51 @@
+// This file is part of Eigen, a lightweight C++ template library
+// for linear algebra.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+#include <sstream>
+
+#include "main.h"
+
+template<typename From, typename To>
+void test_conversion() {
+  typedef Array<From, Dynamic, 1> ArrayXFrom;
+  typedef Array<To, Dynamic, 1> ArrayXTo;
+  typedef Array<double, Dynamic, 1> ArrayXDouble;
+
+  Index size = internal::random<Index>(1, EIGEN_TEST_MAX_SIZE);
+  double from_min = static_cast<double>((std::numeric_limits<From>::min)());
+  double from_range = static_cast<double>((std::numeric_limits<From>::max)()) - from_min;
+
+  // ArrayXFrom::Random() only generates 32-bit values (#2749), so we generate
+  // doubles and scale to fit the range.
+  ArrayXDouble doubles = (ArrayXDouble::Random(size)+1.0)*(from_range/2.0) + from_min;
+  ArrayXFrom from = doubles.template cast<From>();
+  ArrayXTo to(size);
+  for (Index i = 0; i < size; ++i) {
+    to(i) = static_cast<To>(from(i));
+  }
+  VERIFY_IS_APPROX(from.template cast<To>(), to);
+}
+
+template<typename To>
+void test_conversion_to() {
+  CALL_SUBTEST((test_conversion<int64_t, To>()));
+  CALL_SUBTEST((test_conversion<uint64_t, To>()));
+  CALL_SUBTEST((test_conversion<int32_t, To>()));
+  CALL_SUBTEST((test_conversion<uint32_t, To>()));
+  CALL_SUBTEST((test_conversion<int16_t, To>()));
+  CALL_SUBTEST((test_conversion<uint16_t, To>()));
+  CALL_SUBTEST((test_conversion<int8_t, To>()));
+  CALL_SUBTEST((test_conversion<uint8_t, To>()));
+}
+
+EIGEN_DECLARE_TEST(float_conversion)
+{
+  for(int i = 0; i < g_repeat; i++) {
+    CALL_SUBTEST(test_conversion_to<float>());
+    CALL_SUBTEST(test_conversion_to<double>());
+  }
+}