[PATCH] Fix up wi::lrshift (PR c++/69399)

[Jakub Jelinek]

On Tue, Jan 26, 2016 at 01:55:41PM -0800, Mike Stump wrote:
> On Jan 26, 2016, at 1:26 PM, Jakub Jelinek <jakub@redhat.com> wrote:
> > will do cc1plus size comparison afterwards.
> 
> We know the dynamic check is larger.  You can’t tell the advantage of
> speed from size.  Better would be to time compiling any random large
> translation unit.
> 
> Nice to see that only 14 calls remain, that’s way better than the 34 I
> thought.

So, it seems probably the PR65656 changes made things actually significantly
worse, while I see a (small) difference in the generated code between the two
patches if I compile say tree-ssa-ccp.c with g++ 5.x, in the bootstrapped
compiler there is no difference at all, the compilers with either patch
have identical objdump -dr cc1plus.  Already at *.gimple time all the
relevant __builtin_constant_p are resolved and it seems all to 0.

So please agree on one of the two patches (don't care which), and I'll try
to distill a testcase to look at for PR65656.

	Jakub