[Bug tree-optimization/106192] [11/12/13 Regression] ICE in vect_loop_versioning, at tree-vect-loop-manip.cc:3522

["rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106192

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |matz at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |needs-bisection
      Known to work|                            |10.3.0
           Priority|P3                          |P2
      Known to fail|                            |11.3.0, 12.1.0, 13.0
   Last reconfirmed|                            |2022-07-05

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  LOOP_REQUIRES_VERSIONING_FOR_SIMD_IF_COND is _15 and we have the
loop header

<bb 4> [local count: 696725737]:
# i.2_29 = PHI <1(3), i.2_22(11)>
# ivtmp_24 = PHI <100(3), ivtmp_16(11)>
.GOMP_SIMD_LANE (simduid.6_17(D), 0, _12);
_13 = i.2_29 + -1;
_18 = (integer(kind=8)) _13;
_19 = a[_18];
_20 = _19 + 1;
a[_18] = _20;
i.2_22 = i.2_29 + 1;
_3 = j.0_28 + 1;
_15 = _3 <= 59;
.GOMP_SIMD_LANE (simduid.6_17(D), 0, _15);
_8 = _19 + 2;
a[_18] = _8;
ivtmp_16 = ivtmp_24 - 1;
if (ivtmp_16 != 0)
  goto <bb 11>; [87.50%]
else
  goto <bb 12>; [12.50%]

so the bb != loop->header part of the assert already fires.  The condition
is loop invariant but it wasn't hoisted for some reason.  Or rather it
looks like we unrolled the loop once which we might not do to .GOMP_SIMD_LANE
bbs IIRC.

unroll-and-jam does this.