octave-3.4.3+gcc46 on OS X 10.4/powerpc, test hangs in bsxfun

[David Fang]

Hello octavians,

Recently, I've been trying to port octave-3.4.3 for OS X 10.4/powerpc in 
fink, and have encountered hanging in the test suite.
I initially tried the system compiler (g++-4.0.1) but encountered
the following issue: https://savannah.gnu.org/bugs/?30685
where on startup, octave would segfault in sigemptyset().
I then switched to gcc-4.6.2, which has shown decent test results for 
powerpc-apple-darwin8 
[http://gcc.gnu.org/ml/gcc-testresults/2011-10/msg03272.html].
With gcc-4.6, the test suite hangs starting in bsxfun.cc, specifically on:

octave:1> f = @minus;
octave:2> bsxfun (f, ones(4, 0), ones(4, 4))
*** wait forever... ^C^C^C

I've added some debug hooks to trace what's going on and also have a gdb 
stacktrace (from ../run-octave -g ...):

\-{ Fbsxfun
| :  arguments checked.
| :  func.is_builtin || is_function_handle...
| \-{ maybe_optimized_builtin
| | \-{ maybe_fill_table
| | | :  filling...
| | /-} maybe_fill_table
| | \-{ bsxfun_builtin_lookup
| | /-} bsxfun_builtin_lookup
| | :  op != bsxfun_builtin_unknown
| | \-{ octave_value bsxfun_forward_op(const octave_value&, const 
octave_value&) [with NDA = NDArray, NDA (* bsxfun_op)(const NDA&, const 
NDA&) = bsxfun_sub]
| | | :  extracted x
| | | :  extracted y
| | | \-{ NDArray bsxfun_sub(const NDArray&, const NDArray&)
| | | | \-{ Array<R> do_bsxfun_op(const Array<X>&, const Array<Y>&, void 
(*)(std::size_t, R*, const X*, const Y*), void (*)(std::size_t, R*, X, 
const Y*), void (*)(std::size_t, R*, const X*, Y)) [with R = double, X = 
double, Y = double, std::size_t = long unsigned int]
| | | | | :  i = 0
| | | | | :  i = 1
| | | | | \-{ lo_error_handler
error: bsxfun: nonconformant dimensions: 4x0 and 4x4
| | | | | | \-{ octave_throw_execution_exception
^C
Program received signal SIGINT, Interrupt.
0x9143b3a0 in uw_frame_state_for ()
(gdb) where
#0  0x9143b3a0 in uw_frame_state_for ()
#1  0x9143cb7c in _Unwind_RaiseException ()
#2  0x03be6148 in __cxa_throw () at settings.h:338
#3  0x0038acc8 in octave_throw_execution_exception ()
#4  0x0123ec08 in _ZL16lo_error_handlerPKcz ()
#5  0x02c40d90 in do_bsxfun_op<double, double, double> ()
#6  0x02438d24 in bsxfun_sub ()
#7  0x04a49008 in bsxfun_forward_op<NDArray, &(bsxfun_sub(NDArray const&, 
NDArray const&))> () at settings.h:338
#8  0x04a59460 in Fbsxfun () at settings.h:338
#9  0x012f95d0 in octave_builtin::do_multi_index_op ()
#10 0x012f8460 in octave_builtin::subsref ()
#11 0x012f9074 in octave_builtin::subsref ()
#12 0x013b0ed4 in octave_value::subsref ()
#13 0x01445908 in tree_index_expression::rvalue ()
#14 0x01446348 in tree_index_expression::rvalue ()
#15 0x01440dc0 in tree_index_expression::rvalue1 ()
#16 0x01436710 in tree_evaluator::visit_statement ()
#17 0x0145ff10 in tree_statement::accept ()
#18 0x0143118c in tree_evaluator::visit_statement_list ()
#19 0x01460030 in tree_statement_list::accept ()
#20 0x01298538 in main_loop ()
#21 0x01242c40 in octave_main ()
#22 0x00002e28 in _start ()
#23 0x00002b2c in start ()

The full trail of my debugging efforts is at:
http://paste.lisp.org/display/125952
(starting at annotation #5)

The thrown exception looks like an empty class, thrown by value, and 
somehow this winds up in some infinite loop.

My questions:
what is supposed to happen after "bsxfun: nonfconformant dimensions"?
I would expect the stack to unwind up to the next handler when thrown, but 
that doesn't seem to be happening?

Suspects:
gcc46 miscompilation?

Any help/tips/leads greatly appreciated.  Thanks.

Fang

--
David Fang
http://www.csl.cornell.edu/~fang/