https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84955
--- Comment #4 from cesar at gcc dot gnu.org --- It fails in C with this: #pragma acc parallel loop tile(2,3) for (i = 1; i < 10; i++) for (j = 1; j < 10; j++) for (;;) ; It must be that empty loop that tripping up the oacc tile lowering code.