Re: [Qemu-devel] [PATCH v2 for 2.5] QEMU does not care about left shifts of signed negative values

[Paolo Bonzini]

On 17/11/2015 19:19, Peter Maydell wrote:
> That doesn't seem like more than half-good news to me. In particular,
> if ubsan is still diagnosing these cases and they're still a
> problem in some constant expressions

Constant expressions are standardese for e.g.

static int x = 1 << 31;

It doesn't mean _all_ constants, and the warning only triggers with
-pedantic.

Regarding ubsan, give them some time to answer. :)

Paolo

> If the GCC folks don't want to go any further than that then
> I think we should prefer to avoid this UB. (And there's still
> the question of clang's position on this.)