http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56982
--- Comment #13 from Bernd Edlinger <bernd.edlinger at hotmail dot de> --- Created attachment 30431 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30431&action=edit another example of wrong compilation This is another example where the optimization can go wrong. The attached program produces expected results if compiled with -O0: x=0, a=1 x=1, a=1 a=1 But if compiled with -O3 and if the value "a" is placed in a register the result is like this: x=0, a=1 x=1, a=0 a=0 That is because longjmp has more semantic than just a branch: It branches to the setjmp, and restores all callee saved registers to the previos value.
