https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112385
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
We can even do it if we know the unsigned value does not have the last bit set.
That is:
```
int f(int a, unsigned b, int c)
{
b &= 0xffff;
return (c >> a) ^ (b >> a);
}
```
Note clang(LLVM) does not handle the above.
The way LLVM handles the others is it changes ashift to lshift if the value is
known to be non-negative. But since in the gimple level we are dealing with
types we can't do that in a nice way; RTL level on the other hand yes that can
be done (though nonzero bits is limited there).
