https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88998
Marc Glisse <glisse at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2019-01-23
Ever confirmed|0 |1
--- Comment #1 from Marc Glisse <glisse at gcc dot gnu.org> ---
Indeed. Constructing {a,b,0,0} is done by constructing {a,b}, {0,0}, and
concatenating them. _mm_cvtepi32_pd starts with selecting the initial V2SI of a
V4SI. Naturally, the compiler tries to combine them, and finds sse2_cvtpi2pd to
convert directly from V2SI to V2DF. Without this simplification, everything
would have used SSE.
