"I added a printf("%f\n",a) to the end of the file so the compiler wouldn't optimize the whole thing away. On my Cure 2 Duo 2.33Ghz, I got for gcc -O3:
1000000000.000000
real 0m4.396s user 0m4.386s sys 0m0.007s
and for gcc -O3 -flto -fwhole-program:
1000000000.000000
real 0m1.312s user 0m1.308s sys 0m0.003s"
Yet another case of somebody thinking they're making a clever comparison by forgetting to set their compiler flags properly.