[Bug target/78176] [MIPS] miscompiles ldxc1 with large pointers on 32-bits

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78176

--- Comment #19 from Richard Biener <rguenth at gcc dot gnu.org> ---
I agree with the comments that this (if at all) needs to be fixed at RTL
expansion time where we already do quite some "hacks" for sizetype
in POINTER_PLUS_EXPR context:

    case POINTER_PLUS_EXPR:
      /* Even though the sizetype mode and the pointer's mode can be different
         expand is able to handle this correctly and get the correct result out
         of the PLUS_EXPR code.  */
      /* Make sure to sign-extend the sizetype offset in a POINTER_PLUS_EXPR
         if sizetype precision is smaller than pointer precision.  */
      if (TYPE_PRECISION (sizetype) < TYPE_PRECISION (type))
        treeop1 = fold_convert_loc (loc, type,
                                    fold_convert_loc (loc, ssizetype,
                                                      treeop1));
      /* If sizetype precision is larger than pointer precision, truncate the
         offset to have matching modes.  */

but I don't see from the comments in this bug what the actual stmt is the
critical one.