[Bug tree-optimization/108498] [11/12/13 Regression] ppc64 big endian generates uninitialized reads with -fstore-merging

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108498

--- Comment #20 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 54335
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54335&action=edit
gcc13-pr108498.patch

Untested fix (well, checked on both testcases on x86_64-linux -m32/-m64 and
on the first one for powerpc64-linux -m64).