The m68k-linux failure for the various omp atomic tests is due to the fact that BIGGEST_ALIGNMENT is 16 bits on that platform. I think it's pretty reasonable to assume that if something is aligned to BIGGEST_ALIGNEMENT, then it can be considered "aligned".
Tested on x86_64-linux and m68k-linux cross. r~
* omp-low.c (expand_omp_atomic): Assume anything aligned to BIGGEST_ALIGNMENT is aligned. diff --git a/gcc/omp-low.c b/gcc/omp-low.c index a4bfb84..4e1c2ba 100644 --- a/gcc/omp-low.c +++ b/gcc/omp-low.c @@ -5501,7 +5501,9 @@ expand_omp_atomic (struct omp_region *region) unsigned int align = TYPE_ALIGN_UNIT (type); /* __sync builtins require strict data alignment. */ - if (exact_log2 (align) >= index) + /* ??? Assume BIGGEST_ALIGNMENT *is* aligned. */ + if (exact_log2 (align) >= index + || align * BITS_PER_UNIT >= BIGGEST_ALIGNMENT) { /* Atomic load. */ if (loaded_val == stored_val