Re: [3.3 branch] IA64 bootstrap failure

[Jim Wilson <wilson at tuliptree dot org>]

Andreas Schwab wrote:
> Running the same (stage2) compiler command on the command line produces
> output that is the same as the output from the stage1 compiler.  So it
> indeed looks like it's dependent on the environment size.

I've debugged problems like this before.  You vary the environment size 
until you can reproduce the problem, and then you debug two compilers in 
parallel with different environment sizes until you figure out why they 
emit different code.  Probably an uninitialized variable or a 
stray/out-of-bounds memory reference somewhere.  Another possibly is 
that addresses are being used (e.g. in a hash table) and there is a 
latent bug in the code.

You can write a shell script to try different environment sizes in a 
loop.  Start with an environment size as close to zero as you can get, 
then add 8 bytes to the environment after every gcc run until the output 
changes.

I will try doing this with a cross, but I am not sure if I will be 
successful since I don't have the real testcase, I will have to fake one 
up which may not be good enough to reproduce the problem.

Jim