[Bug middle-end/116997] [13/14/15 Regression] Wrong bitfield accesses since r13-3219-g25413fdb2ac249

[avieira at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116997

--- Comment #5 from avieira at gcc dot gnu.org ---
I checked it locally and Pinski's recommended change does seem to fix the
codegen for this case. I end up with:
MEM <vector(2) unsigned int> [(void *)Ptr.0_1] = { 7, 6291456 };

I am regression testing the change now on aarch64_be-none-elf. @Stefan maybe
you can test it on your z13 ?

The change in question is:
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -13712,6 +13712,8 @@ fold_ternary_loc (location_t loc, enum tree_code code,
tree type,
        {
          unsigned HOST_WIDE_INT bitpos = tree_to_uhwi (op2);
          unsigned bitsize = TYPE_PRECISION (TREE_TYPE (arg1));
+         if (BYTES_BIG_ENDIAN)
+           bitpos = TYPE_PRECISION (type) - bitpos - bitsize;
          wide_int tem = (wi::to_wide (arg0)
                          & wi::shifted_mask (bitpos, bitsize, true,
                                              TYPE_PRECISION (type)));