On Wed, May 04, 2016 at 03:06:04PM -0700, John Denker wrote: > On 05/04/2016 02:56 PM, H. Peter Anvin wrote: > >> Beware that shifting by an amount >= the number of bits in the > >> word remains Undefined Behavior. > > > This construct has been supported as a rotate since at least gcc2. > > How then should we understand the story told in commit d7e35dfa? > Is the story wrong?
I don't think Linux runs on a system where it would make a difference (like a VAX), and also gcc always converts it before it could. Even UBSan should not complain because it runs after the conversion to ROTATE. So it's unlikely to be a pressing issue. -Andi -- a...@linux.intel.com -- Speaking for myself only.