Wrong optimiszed floatting point code : a same code 
in a function or in a struct (member of static function)
produces a different result when -O? flag is enabled.
-ffloat-store flag produces a better (but longer) code.
(and sometimes with -finline-functions (following the context))
(more strange cases are: using std::cout or printf may change 
the final result !)

Without -O? flag, the code is always right.

Release:
g++ version 2.95.4(20011002), 3.0.4, 3.1

Environment:
Linux Intel i686 (Pentium III)

How-To-Repeat:
Runs the same code with or without optimization flags (-O, -O2, -O3),
the code may give bad result (the good one is 0)
Longer details (flags ...) are available for 2 test cases.