On 04/23/2014 03:17 AM, Petr Machata wrote:
Wouldn't something like this get us off the hook as well?
- (var) |= (typeof (var)) __s.i << ((nth) * 7); \
+ (var) |= (typeof (var)) \
+ (((uint64_t) (typeof (var)) __s.i) << ((nth) * 7)); \
We are really only using the bitfield trick to avoid having to
sign-extend by hand, but we can shift unsigned without losing anything.
It gets us off the hook, but might introduce a 64-bit shift where
only a 32-bit shift was required.
Sadly, (unsigned typeof(var)) doesn't work. ;-)
But I gave the multiplication change a look, and the compiler is in fact
optimizing the multiplication by a power of 2 back into a shift.