[ARROW-13602] [C++] Tests dereferencing type-punned pointer compiler warnings

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 6.0.0
• Component/s: C++
• Labels: pull-request-available
• External issue URL: https://github.com/apache/arrow/issues/29245
• Assignee: Keith Kraus
• Reporter: Keith Kraus
• Created: 11/Aug/21 04:17
• Updated: 11/Jan/23 08:34
• Resolved: 19/Aug/21 09:32

Description

Using gcc9:
 

In file included from /home/keith/miniconda3/envs/dev/include/gtest/gtest.h:375,
                 from /home/keith/miniconda3/envs/dev/include/gmock/internal/gmock-internal-utils.h:47,
                 from /home/keith/miniconda3/envs/dev/include/gmock/gmock-actions.h:51,
                 from /home/keith/miniconda3/envs/dev/include/gmock/gmock.h:59,
                 from /home/keith/git/arrow/cpp/src/arrow/util/bit_util_test.cc:30:
/home/keith/git/arrow/cpp/src/arrow/util/bit_util_test.cc: In member function 'virtual void arrow::BitUtil_ByteSwap_Test::TestBody()':
/home/keith/git/arrow/cpp/src/arrow/util/bit_util_test.cc:1835:32: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
 1835 |   EXPECT_EQ(BitUtil::ByteSwap(*reinterpret_cast<float*>(&srci32)),
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/keith/git/arrow/cpp/src/arrow/util/bit_util_test.cc:1836:14: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
 1836 |             *reinterpret_cast<float*>(&expectedi32));
      |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/keith/git/arrow/cpp/src/arrow/util/bit_util_test.cc:1838:32: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
 1838 |   EXPECT_EQ(BitUtil::ByteSwap(*reinterpret_cast<double*>(&srci64)),
      |                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/keith/git/arrow/cpp/src/arrow/util/bit_util_test.cc:1839:14: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
 1839 |             *reinterpret_cast<double*>(&expectedi64));
      |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Issue Links

• links to: GitHub Pull Request #10945