g++ 7.1.1 crashes on this code when compiled with -O2 on x86_64:

> #include <gtest/gtest.h>
> #include <boost/uuid/uuid.hpp>
> 
> void crash_gcc7()
> {
>     static const boost::uuids::uuid u = boost::uuids::uuid();
>     EXPECT_EQ(u, u);
> }

This was reduced from a large unittest at work. Further reduced by inlining
gtest & boost headers:

> class AssertionResult {
>   bool success_;
> };
> 
> AssertionResult AssertionSuccess();
> 
> template <typename T1>
> AssertionResult EXPECT_EQ(const T1& expected, const T1& actual) {
>   if (expected == actual) {
>     return AssertionSuccess();
>   }
>   return AssertionSuccess();
> }
> 
> struct uuid
> {
>     // or should it be array<unsigned char, 16>
>     unsigned char data[16];
> };
> 
> bool operator== (uuid const& lhs, uuid const& rhs);
> 
> #include <emmintrin.h>
> 
> __m128i load_unaligned_si128(const unsigned char* p)
> {
>     return _mm_loadu_si128(reinterpret_cast< const __m128i* >(p));
> }
> 
> inline bool operator== (uuid const& lhs, uuid const& rhs)
> {
>     __m128i mm_left = load_unaligned_si128(lhs.data);
>     __m128i mm_right = load_unaligned_si128(rhs.data);
> 
>     __m128i mm_cmp = _mm_cmpeq_epi32(mm_left, mm_right);
> 
>     return _mm_movemask_epi8(mm_cmp) == 0xFFFF;
> }
> 
> void crash_gcc7()
> {
>     static const uuid u = uuid();
>     EXPECT_EQ(u, u);
> }


Note1: The boost implementation had an SSE2 optimized version and a generic
version. The generic version does NOT crash g++.
Note2: emmintrin.h seems to be a GCC header:
/usr/lib64/gcc/x86_64-suse-linux/7/include/emmintrin.h