Seek debugging tip for crash at nullify call

[FX Coudert]

> does someone has an idea how to debug the following program?

Hum. First, make sure it's optimization independent (i.e. it  
segfaults at any -O level). Then make sure this is indeed where the  
first invalid memory reference happens, for example by running your  
program with ElectricFence, valgrind or such tool.

Then, you can generate the tree dump (-fdump-tree-original) of that  
routine and look at it. Or trim down your code to something self- 
contained (which is a pain for runtime errors, I know).

Good luck!
FX