[Bug modula2/114617] gm2 is unable to resolve const expression using relative operators ICE

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114617

--- Comment #3 from Gaius Mulley <gaius at gcc dot gnu.org> ---
With the patch the reported failure examples above pass:

$ gm2 -g -c BasicFileSys.mod
-I../../../../Sandpit/gm2-outside-tree-tests/build/source/m2pp/src/ -fsources
Compiling: BasicFileSys.mod
Pass 0: lexical analysis, parsing, modules and associated filenames
   Module SYSTEM               :
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2cor/SYSTEM.def [m2cor]
   Module M2RTS                :
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/M2RTS.def [m2pim]
   Module RTExceptions         :
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/RTExceptions.def
[m2pim]
   Module BasicFileSys         :
../../../../Sandpit/gm2-outside-tree-tests/build/source/m2pp/src/BasicFileSys.def
   Module BasicFileSys         : BasicFileSys.mod
   Module COROUTINES           :
/home/gaius/opt/lib/gcc/x86_64-pc-linux-gnu/14.0.1/m2/m2pim/COROUTINES.def
[m2pim] (for C)
   Module Size                 : ./Size.def
   Module stat                 : ./stat.def
   Module stdio                : ./stdio.def (for C)
   Module unistd               : ./unistd.def (for C)
   Module fcntl                : ./fcntl.def (for C)
   Module stat0                : ./stat0.def (for C)
   Module SysTypes             : ./SysTypes.def
Pass 1: scopes, enumerated types, imports and exports
Pass 2: constants and types
Pass C: aggregate constants
Pass 3: quadruple generation
Pass 4: gcc tree generation
        symbols to gcc trees
        statements to gcc trees
        gcc trees given to the gcc backend

and

$ gm2 -c -fiso constbool3.mod