Re: [RFC PATCH] Do not sanitize left shifts for -fwrapv

2015-11-18 Thread Marek Polacek
On Tue, Nov 17, 2015 at 02:32:50PM +0100, Paolo Bonzini wrote: > Left shifts into the sign bit is a kind of overflow, and the > standard chooses to treat left shifts of negative values the > same way. > > However, the -fwrapv option modifies the language to one where > integers are defined as two'

[RFC PATCH] Do not sanitize left shifts for -fwrapv

2015-11-17 Thread Paolo Bonzini
Left shifts into the sign bit is a kind of overflow, and the standard chooses to treat left shifts of negative values the same way. However, the -fwrapv option modifies the language to one where integers are defined as two's complement---which also defines entirely the behavior of shifts. Disable