The code below (float.c) fills in a float `f' with
1.00000 by accessing it as an array `fp' of two unsigned integers, and
storing the appropriate value in each element of the array.  The value
printed should therefore be 1.00000, and this is what happens when
compiling without optimization options.  With -O2 and above, the value
printed is 2.0000.  Qualifying both `f' and `fp' as volatile seems to
eliminate the wrong behavior.

Release:
gcc version 2.96 20000731

Environment:
Red Had Linux 7.1, kernel 2.4.2-2 i686 unknown

How-To-Repeat:
gcc -O3 float.c -o float ; ./float