[Bug tree-optimization/127879] Improve fold_using_range::range_from_readonly_var for STRING_CSTs and RAW_DATA_CST

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=127879

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 65835
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=65835&action=edit
gcc17-pr127879.patch

Untested fix.