The optimizations would be nice, but the REG_NOTEs are not always (alright, hardly ever) present to select the optimizations above. So I need to get more invasive. I've made this test program to test the "neg; jeq" optimization.
extern int func();
int a = func();
if(a == 0)
Check out the debug output files, and track down where the live register usage is tracked. I should be able to root around in the internals to properly check for valid cases.