[Bug target/85381] [og7, nvptx, openacc] parallel-loop-1.c fails with default vector length 128

[vries at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85381

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
I minimized this failure, and ran into PR 80035/81069, so I've backported the
fix from trunk: https://gcc.gnu.org/ml/gcc-patches/2018-04/msg00774.html