[Bug target/99754] [sse2] new _mm_loadu_si16 and _mm_loadu_si32 implemented incorrectly

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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99754

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by hongtao Liu
<liuhongt@gcc.gnu.org>:

https://gcc.gnu.org/g:85568e505c3b06708ec0fb21d1ab4f78e0c66896

commit r11-9699-g85568e505c3b06708ec0fb21d1ab4f78e0c66896
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Mon Mar 14 10:44:38 2022 +0100

    i386: Fix up _mm_loadu_si{16,32} [PR99754]

    These intrinsics are supposed to do an unaligned may_alias load
    of a 16-bit or 32-bit value and store it as the first element of
    a 128-bit integer vector, with all other elements cleared.

    The current _mm_storeu_* implementation implements that correctly, uses
    __*_u types to do the store and extracts the first element of a vector into
    it.
    But _mm_loadu_si{16,32} gets it all wrong.  It performs an aligned
    non-may_alias load and because _mm_set_epi{16,32} has the args reversed,
    it also inserts it into the last vector element instead of first.

    The following patch fixes that.

    Note, while the Intrinsics guide for _mm_loadu_si32 says SSE2,
    for _mm_loadu_si16 it says strangely SSE.  But the intrinsics
    returns __m128i, which is only defined in emmintrin.h, and
    _mm_set_epi16 is also only SSE2 and later in emmintrin.h.
    Even clang defines it in emmintrin.h and ends up with inlining
    failure when calling _mm_loadu_si16 from sse,no-sse2 function.
    So, isn't that a bug in the intrinsic guide instead?

    2022-03-14  Jakub Jelinek  <jakub@redhat.com>

            PR target/99754
            * config/i386/emmintrin.h (_mm_loadu_si32): Put loaded value into
            first   rather than last element of the vector, use __m32_u to do
            a really unaligned load, use just 0 instead of (int)0.
            (_mm_loadu_si16): Put loaded value into first rather than last
            element of the vector, use __m16_u to do a really unaligned load,
            use just 0 instead of (short)0.

            * gcc.target/i386/pr99754-1.c: New test.
            * gcc.target/i386/pr99754-2.c: New test.