[Aldor-l] Bigint bug(!)

[Gabriel Dos Reis]

pip88nl at gmail.com writes:

| On Sat, Aug 16, 2008 at 12:49:21PM -0400, Stephen Watt wrote:
| > Such a huge list of bugs is very surprising.   Which C compiler are you using?
| > It may be as Gaby suggested that more aggressive optimization is
| > changing the behaviour of code when ints wrap around.  -- Stephen
| 
| I am using gcc 4.1 and glibc 2.3. My guess is indeed the optimisation.
| I'll do some tests with different optimisation settings.

You can experiment by rebuilding everything with -fwrapv (for ALL
invocations of GCC) to see how things turn out.

-fwrapv instructs GCC to assume that signed overflow arithmetic wraps
around.  In return you don't benefit from optimzations based on value
range propopation (typically in loops).

-- Gaby