Confirmed in gcc-linaro-4.4-2010.09-1 on i686.  See:
 http://ex.seabright.co.nz/build/gcc-linaro-4.4-2010.09-1/gcc-linaro-4.4-2010.09-1-i686-lucid-cbuild3-scorpius.tar.xz

for a binary build.  Note that name=0 in the call to get_fileinfo().  I think this ends up being passed to strcmp() via splay_tree_splay() causing the segfault.  This means that the global input_filename is null.

Backtrace:

Program received signal SIGSEGV, Segmentation fault.
0x00688198 in ?? () from /lib/tls/i686/cmov/libc.so.6
(gdb) back
#0  0x00688198 in ?? () from /lib/tls/i686/cmov/libc.so.6
#1  0x086c3387 in splay_tree_splay (sp=0x89208e8, key=144478368) at ../../gcc-linaro-4.4-2010.09-1/libiberty/splay-tree.c:148
#2  0x086c380b in splay_tree_lookup (sp=0x89208e8, key=0) at ../../gcc-linaro-4.4-2010.09-1/libiberty/splay-tree.c:389
#3  0x081204f4 in get_fileinfo (name=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/c-lex.c:114
#4  0x0809c3a8 in cxx_make_type (code=RECORD_TYPE) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/lex.c:659
#5  0x0809c401 in make_class_type (code=RECORD_TYPE) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/lex.c:670
#6  0x0805dcb6 in build_ptrmemfunc_type (type=0xb37170d0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/decl.c:7087
#7  0x0807ad23 in tsubst (t=0xb48a88f0, args=<value optimized out>, complain=tf_error, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:9585
#8  0x0807a3f1 in tsubst (t=0xb48a89c0, args=0xb3702c60, complain=tf_error, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:9248
#9  0x0807e7c3 in tsubst_arg_types (arg_types=<value optimized out>, args=<value optimized out>, complain=<value optimized out>, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:8957
#10 0x0807e704 in tsubst_arg_types (arg_types=<value optimized out>, args=<value optimized out>, complain=<value optimized out>, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:8926
#11 0x0807e704 in tsubst_arg_types (arg_types=<value optimized out>, args=<value optimized out>, complain=<value optimized out>, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:8926
#12 0x0807e957 in tsubst_function_type (t=0xb4780a90, args=<value optimized out>, complain=tf_error, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:9052
#13 0x0807a1ba in tsubst (t=0xb4780a90, args=0xb3702c60, complain=tf_error, in_decl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:9660
#14 0x08081536 in get_mostly_instantiated_function_type (decl=0xb3e96680) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/pt.c:16102
#15 0x080e7db0 in write_encoding (decl=0xb3e96680) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:703
#16 0x080e7aef in write_local_name (decl=0xb3da2058, ignore_local_scope=<value optimized out>) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:1498
#17 write_name (decl=0xb3da2058, ignore_local_scope=<value optimized out>) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:799
#18 0x080e7d24 in write_encoding (decl=0xb3da2058) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:695
#19 0x080e7e3f in write_mangled_name (decl=0xb3da2058, top_level=<value optimized out>) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:665
#20 0x080e8ed4 in mangle_decl_string (decl=0xb3da2058) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:2801
#21 mangle_decl (decl=0xb3da2058) at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/mangle.c:2823
#22 0x0841f551 in decl_assembler_name (decl=0xb3da2058) at ../../gcc-linaro-4.4-2010.09-1/gcc/tree.c:361
#23 0x0843baa8 in make_decl_rtl (decl=0xb3da2058) at ../../gcc-linaro-4.4-2010.09-1/gcc/varasm.c:1372
#24 0x081cebae in expand_expr_real_1 (exp=0xb3da2058, target=<value optimized out>, tmode=<value optimized out>, modifier=EXPAND_CONST_ADDRESS, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:7314
#25 0x081d08f3 in expand_expr_real (exp=0xb3da2058, target=0xb3714bf4, tmode=SImode, modifier=EXPAND_CONST_ADDRESS, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:7154
#26 0x081d4454 in expand_expr (exp=0xb3da2058, target=0xb3714bf4, tmode=SImode, modifier=EXPAND_STACK_PARM) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.h:539
#27 expand_expr_addr_expr_1 (exp=0xb3da2058, target=0xb3714bf4, tmode=SImode, modifier=EXPAND_STACK_PARM) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:6851
#28 0x081d4550 in expand_expr_addr_expr_1 (exp=0xb3d97630, target=0xb3714bf4, tmode=SImode, modifier=EXPAND_STACK_PARM) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:6898
#29 0x081cc7a9 in expand_expr_addr_expr (exp=0xb3dfbac0, target=<value optimized out>, tmode=<value optimized out>, modifier=EXPAND_STACK_PARM, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:6957
#30 expand_expr_real_1 (exp=0xb3dfbac0, target=<value optimized out>, tmode=<value optimized out>, modifier=EXPAND_STACK_PARM, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:9301
#31 0x081d09c8 in expand_expr_real (exp=0xb3dfbac0, target=0xb3714bf4, tmode=VOIDmode, modifier=EXPAND_STACK_PARM, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:7148
#32 0x081539c1 in expand_expr (arg=0xbfffeeb0, argblock=<value optimized out>, flags=<value optimized out>, variable_size=0, reg_parm_stack_space=0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.h:539
#33 store_one_arg (arg=0xbfffeeb0, argblock=<value optimized out>, flags=<value optimized out>, variable_size=0, reg_parm_stack_space=0) at ../../gcc-linaro-4.4-2010.09-1/gcc/calls.c:4135
#34 0x0815545c in expand_call (exp=0xb3716578, target=0x0, ignore=1) at ../../gcc-linaro-4.4-2010.09-1/gcc/calls.c:2753
#35 0x081cdfbc in expand_expr_real_1 (exp=0xb3716578, target=<value optimized out>, tmode=<value optimized out>, modifier=EXPAND_NORMAL, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:8133
#36 0x081d09c8 in expand_expr_real (exp=0xb3716578, target=0xb7eb6310, tmode=VOIDmode, modifier=EXPAND_NORMAL, alt_rtl=0x0) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.c:7148
#37 0x0830b27b in expand_expr (exp=0xb3716578) at ../../gcc-linaro-4.4-2010.09-1/gcc/expr.h:539
#38 expand_expr_stmt (exp=0xb3716578) at ../../gcc-linaro-4.4-2010.09-1/gcc/stmt.c:1370
#39 0x0861a4b6 in expand_gimple_basic_block (bb=<value optimized out>) at ../../gcc-linaro-4.4-2010.09-1/gcc/cfgexpand.c:1947
#40 0x0861b5ea in gimple_expand_cfg () at ../../gcc-linaro-4.4-2010.09-1/gcc/cfgexpand.c:2350
#41 0x0828a276 in execute_one_pass (pass=0x8880f00) at ../../gcc-linaro-4.4-2010.09-1/gcc/passes.c:1280
#42 0x0828a4cc in execute_pass_list (pass=0x8880f00) at ../../gcc-linaro-4.4-2010.09-1/gcc/passes.c:1329
#43 0x083514ed in tree_rest_of_compilation (fndecl=0xb3e96680) at ../../gcc-linaro-4.4-2010.09-1/gcc/tree-optimize.c:420
#44 0x08471d8b in cgraph_expand_function (node=0xb3df9880) at ../../gcc-linaro-4.4-2010.09-1/gcc/cgraphunit.c:1047
#45 0x084730a7 in cgraph_expand_all_functions () at ../../gcc-linaro-4.4-2010.09-1/gcc/cgraphunit.c:1106
#46 cgraph_optimize () at ../../gcc-linaro-4.4-2010.09-1/gcc/cgraphunit.c:1310
#47 0x08097a55 in cp_write_global_declarations () at ../../gcc-linaro-4.4-2010.09-1/gcc/cp/decl2.c:3657
#48 0x0831727f in compile_file (argc=3, argv=0xbffff704) at ../../gcc-linaro-4.4-2010.09-1/gcc/toplev.c:981
#49 do_compile (argc=3, argv=0xbffff704) at ../../gcc-linaro-4.4-2010.09-1/gcc/toplev.c:2197
#50 toplev_main (argc=3, argv=0xbffff704) at ../../gcc-linaro-4.4-2010.09-1/gcc/toplev.c:2229
#51 0x0812d22b in main (argc=3, argv=0xbffff704) at ../../gcc-linaro-4.4-2010.09-1/gcc/main.c:35