I hope you will find this information usefull.

I am not in the linux-kernel list so, if posible, I would like to be
personally CC'ed the answers/comments sent to the list in response to
this posting.

I think I heve found a bug in gcc. I have tried both egcs 1.1.2 (gcc
2.91.66) and gcc 2.95.2 versions.

I am attaching you a simplified test program ('bug.c', a really simple
program).

To generate the faulty program from correct code compile as:
  gcc -O2 -o bug bug.c

You can generate good code in two ways:
1. Compiling with:
  gcc -fno-strength-reduce -O2 -o bug bug.c

   So the problem is with the option -fstrength-reduce which is 
   active with the common '-O2' optimization option.

2. Uncomment the printf at line 34. Bugs are surprising.

I have also sent the bug report to the gcc maintainers.

Is it really a bug?

Thank you,

David Llorens.