On Sun, Jan 31, 2016 at 06:02:35PM -0600, Segher Boessenkool wrote: > On Mon, Feb 01, 2016 at 08:46:42AM +1030, Alan Modra wrote: > > The comment says this test is supposed to prevent "a narrower > > operation than requested", but it actually only allows a larger > > subreg, not one the same size. Fix that. > > > > Bootstrapped and regression tested powerpc64-linux. OK for stage1? > > > > Note that this bug was found when investigating why gcc-6 does not > > suffer from pr69548, ie. this bug was masking a powerpc backend bug. > > It sounds like you have a testcase, can we see it please?
The testcase in pr69548 will show changes in rtl.. > And, just a missed optimisation, not a bug, right? Yes, not a bug, and only presumed a missed optimisation. I don't actually have a testcase that shows worse code. All I have is a comment that makes sense to me, that doesn't agree exactly with the code, and some understanding how the code may have been accidentally written the way it is. -- Alan Modra Australia Development Lab, IBM
