[Boost-bugs] [Boost C++ Libraries] #11135: SIMD optimizations for UUIDs break operator< comparisons

Subject: [Boost-bugs] [Boost C++ Libraries] #11135: SIMD optimizations for UUIDs break operator< comparisons
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-03-23 20:20:54

#11135: SIMD optimizations for UUIDs break operator< comparisons
----------------------------------------+------------------------
 Reporter:  Krishna Ersson <kersson@…>  |      Owner:  atompkins
     Type:  Bugs                        |     Status:  new
Milestone:  To Be Determined            |  Component:  uuid
  Version:  Boost 1.57.0                |   Severity:  Regression
 Keywords:  uuid simd                   |
----------------------------------------+------------------------
 The addition of SIMD optimizations for UUIDs in Boost 1.57 causes
 `operator<` to fail.  Here's an example test case that now fails unless
 SIMD optimizations are turned off via `#define BOOST_UUID_NO_SIMD`.
 {{{#!c++
 BOOST_AUTO_TEST_CASE(testUuidBasicComparisons)
 {
     auto uuid1 =
 boost::uuids::string_generator()("0123456789abcdef0123456789abcdee");
     auto uuid2 =
 boost::uuids::string_generator()("0123456789abcdef0123456789abcdef");

     // These pass.
     BOOST_CHECK(uuid1 <= uuid1);
     BOOST_CHECK(uuid1 >= uuid1);
     BOOST_CHECK(uuid1 == uuid1);
     BOOST_CHECK(uuid1 != uuid2);
     BOOST_CHECK(uuid1 <= uuid2);
     BOOST_CHECK(uuid2 >= uuid1);

     // These fail, but are expected to fail.
     BOOST_CHECK(uuid1 > uuid2);
     BOOST_CHECK(uuid2 < uuid1);

     // These fail, but should pass.
     BOOST_CHECK(uuid1 < uuid2);
     BOOST_CHECK(uuid2 > uuid1);
 }
 }}}
 When I step through the code, I find that the `operator<` function in
 `boost/uuid/detail/uuid_x86.hpp` considers the two UUIDs in the test case
 to be equal, hence `(uuid1 < uuid2)` and `(uuid1 > uuid2)` both evaluate
 to `false`.  Something is wrong with this code.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11135>
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