Re: Redundant limit check for switch

[Paolo Bonzini]

Why can't this information be used to optimize comparisons?
 

My patch caused GCC to infer that x & 7 > 7 is false.  But I couldn't 
think of a quick way to use this to optimize away the check, because 
then GCC crashed.

Does it work only for consecutive ands?
Or is it just an early constant folding:
return (x + 1) & (0x0f & 0x0c & 0x3ff & 0xff);
?

In this case, it is.

Paolo