Eljay, Though I agree with your point about the standards and undefined behavior, I do believe that Ulf has identified a quality of implementation issue. Would you not agree that compile-time expression evaluation should mimic run-time as much as possible? Or to put it another way, the more often compile-time and run-time evaluated results diverge, the lower the subject quality of the compiler. If the shift operator at run-time examines only the lower order 5 bits of the shift count (as Ulf's x86 does) then a "high-quality" compile-time expression evaluator ought to do the same. /john -----Original Message----- From: Eljay Love-Jensen [mailto:eljay@xxxxxxxxx] Sent: Tuesday, July 12, 2005 6:46 PM To: Ulf Magnusson; gcc-help@xxxxxxxxxxx Subject: Re: Strange shifting behaviour Hi Ulf, >When shifting an int by its size in bits... That is undefined behavior (implementation dependent), as per C and C++ standards. Ever since C was first taking it's first baby steps. By "undefined behavior", that means any given particular implementation can: + not do anything + do what you expect + SEGV + format your hard drive --Eljay
