[Bug target/96827] [10/11 Regression] __m128i from _mm_set_epi32 is backwards with -O3

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96827

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2020-08-28
            Summary|__m128i from _mm_set_epi32  |[10/11 Regression] __m128i
                   |is backwards with -O3       |from _mm_set_epi32 is
                   |                            |backwards with -O3
     Ever confirmed|0                           |1
                 CC|                            |avieira at gcc dot gnu.org,
                   |                            |joel.hutton at arm dot com
   Target Milestone|---                         |10.3
           Priority|P3                          |P2
             Status|UNCONFIRMED                 |NEW

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Ok, I can reproduce that one, started with
r10-4336-g818b3293f4545d899148810f4f7d676b81e989dd
The first difference between the commit right before that one and r10-4336 is
in slp1 pass:
   _5 = dude_[3];
   _6 = (int) _5;
   _7 = dude_[2];
   _8 = (int) _7;
   _9 = dude_[1];
   _10 = (int) _9;
+  vect__11.11_30 = MEM <vector(4) unsigned int> [(unsigned int *)&dude_];
   _11 = dude_[0];
+  vect__12.12_40 = VIEW_CONVERT_EXPR<vector(4) int>(vect__11.11_30);
   _12 = (int) _11;
-  _22 = {_6, _8, _10, _12};
+  _22 = vect__12.12_40;
   _28 = VIEW_CONVERT_EXPR<__m128i>(_22);
   *dude_23(D) = _28;
   dude_ ={v} {CLOBBER};
and that changes the element ordering in the _22 vector, previously it was
dude_[3], dude_[2], dude_[1], dude_[0], newly it is read from the memory which
is the exact opposite order.  The _22 = {_6, _8, _10, _12} is what is in the IL
before slp1, so clearly this is a SLP introduced breakage.