It appears that init_atoms passes minmax_table a 4-byte aligned address.

../boot/ocamlrun ../ocamlopt -nostdlib -I ../stdlib -I ../utils -I
../parsing -I ../typing -I ../bytecomp -I ../asmcomp  -I ../driver -o
ocamldep.opt misc.cmx config.cmx clflags.cmx terminfo.cmx linenum.cmx
warnings.cmx location.cmx longident.cmx syntaxerr.cmx parser.cmx
lexer.cmx parse.cmx  depend.cmx ocamldep.cmx
cd camlp4; make opt.opt
set -e; for i in lib odyl camlp4 meta etc compile; do cd $i; make opt;
cd ..; done
cp odyl_config.ml odyl_config.ppo
../../ocamlcompopt.sh -warn-error A -I ../../otherlibs/dynlink -c
-impl odyl_config.ppo
Bus error (core dumped)
*** Error code 138

Stop in /shared/ocaml-3.09.3/camlp4/odyl.
*** Error code 1


%gdb ocamlopt.opt camlp4/odyl/ocamlopt.opt.core
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This GDB was configured as "sparc64-marcel-freebsd"...
Core was generated by `ocamlopt.opt'.
Program terminated with signal 10, Bus error.
Reading symbols from /lib/libm.so.4...done.
Loaded symbols for /lib/libm.so.4
Reading symbols from /lib/libc.so.7...done.
Loaded symbols for /lib/libc.so.7
Reading symbols from /libexec/ld-elf.so.1...done.
Loaded symbols for /libexec/ld-elf.so.1
#0  0x0000000000250780 in minmax_table ()
(gdb) bt
#0  0x0000000000250780 in minmax_table ()
#1  0x0000000000250848 in init_atoms ()
#2  0x0000000000250ad0 in caml_main ()
#3  0x000000000023ed6c in main ()
(gdb) x/i $pc
0x250780 <minmax_table>:        ldx  [ %o0 ], %g1
(gdb) p/x $o0
$2 = 0x353b84