ppc64le tests fail with clang-10.0.0, -O2 and some flags

[junaruga]

I faced the following error on the latest master branch commit: 396e05c on Fedora rawhide (f33).

This issue does not happen on the clang without flags.
Could you check it? Thank you.

+ clang --version
clang version 10.0.0 (Fedora 10.0.0-1.fc33)
Target: powerpc64le-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin 
+ clang++ --version
clang version 10.0.0 (Fedora 10.0.0-1.fc33)
Target: powerpc64le-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

+ mkdir test/build-clang-with-flags
~/build/BUILD/simde-396e05c694d68c795f0470ef43432eefdfd371f1/test/build-clang-with-flags ~/build/BUILD/simde-396e05c694d68c795f0470ef43432eefdfd371f1
+ pushd test/build-clang-with-flags
+ CC=clang
+ CXX=clang++
+ cmake -DCMAKE_VERBOSE_MAKEFILE:BOOL=ON '-DCMAKE_C_FLAGS=-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -m64 -mcpu=power8 -mtune=power8 -fasynchronous-unwind-tables' '-DCMAKE_CXX_FLAGS=-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -m64 -mcpu=power8 -mtune=power8 -fasynchronous-unwind-tables' ..
...
+ /usr/bin/make -O -j4 V=1 VERBOSE=1
...
+ ./run-tests
...
/x86/sse4_1/mm_cvtepu8_epi16/emul/c  [ ERROR ]
/x86/sse4_1/mm_cvtepu8_epi32/emul/c  Error: /builddir/build/BUILD/simde-396e05c694d68c795f0470ef43432eefdfd371f1/test/x86/sse4.1.c:1193: assertion failed: r.i16[0] == test_vec[i].r.i16[0] (26627 == 3)
Error: child killed by signal 6 (Aborted)    
[ OK    ] [ 0.00000982 / 0.00000754 CPU ]   
...
/x86/sse4_1/mm_cvtepu16_epi32/emul/c [ ERROR ] 
/x86/sse4_1/mm_cvtepu16_epi64/emul/c Error: /builddir/build/BUILD/simde-396e05c694d68c795f0470ef43432eefdfd371f1/test/x86/sse4.1.c:1338: assertion failed: r.i32[0] == test_vec[i].r.i32[0] (-1381660039 == 35449)
Error: child killed by signal 6 (Aborted)    
[ OK    ] [ 0.00000701 / 0.00000514 CPU ]
...
/x86/sse4_1/mm_cvtepu8_epi16/emul/cpp[ ERROR ] 
/x86/sse4_1/mm_cvtepu8_epi32/emul/cppError: /builddir/build/BUILD/simde-396e05c694d68c795f0470ef43432eefdfd371f1/test/build-clang-with-flags/x86/sse4.1.cpp:1193: assertion failed: r.i16[0] == test_vec[i].r.i16[0] (26627 == 3)
Error: child killed by signal 6 (Aborted)
[ OK    ] [ 0.00000998 / 0.00000733 CPU ]  
...
/x86/sse4_1/mm_cvtepu16_epi32/emul/cpp[ ERROR ]
/x86/sse4_1/mm_cvtepu16_epi64/emul/cppError: /builddir/build/BUILD/simde-396e05c694d68c795f0470ef43432eefdfd371f1/test/build-clang-with-flags/x86/sse4.1.cpp:1338: assertion failed: r.i32[0] == test_vec[i].r.i32[0] (-1381660039 == 35449) 
Error: child killed by signal 6 (Aborted)    
[ OK    ] [ 0.00000708 / 0.00000517 CPU ]
...
2286 of 2290 (100%) tests successful, 0 (0%) test skipped.