PATCH to fix -Wrestrict ICE (PR middle-end/83463)

[Jakub Jelinek]

On Mon, Dec 18, 2017 at 10:37:19AM -0700, Martin Sebor wrote:
> On 12/18/2017 10:07 AM, Jakub Jelinek wrote:
> > On Mon, Dec 18, 2017 at 10:00:36AM -0700, Martin Sebor wrote:
> > > On 12/18/2017 08:10 AM, Marek Polacek wrote:
> > > > I'm not entirely up to speed with this code, but this one seemed sufficiently
> > > > obvious: check INTEGRAL_TYPE_P before looking at a tree's min/max value.
> > > > Otherwise, go with maxobjsize.
> > > > 
> > > > Bootstrapped/regtested on x86_64-linux, ok for trunk?
> > > 
> > > Thanks for the fix.  I noticed the problem only comes up when
> > > memcpy is declared without a prototype.  Otherwise, the memcpy
> > > call is eliminated early on (during gimplification?)  So while
> > > avoiding the ICE is obviously a necessary change, I wonder if
> > > this bug also suggests a missing optimization that might still
> > > be relevant (i.e., eliminating memcpy() with a zero size for
> > > a memcpy without a prototype):
> > 
> > No, we shouldn't try to optimize if people mess up stuff.
> 
> Declaring memcpy() without a prototype isn't messing up.  It may
> be poor practice but there's nothing inherently wrong with it.

There is.  Because the last argument is size_t, so calling it with 0
is UB (on LP64, on ILP32 I think it will be optimized normally).

	Jakub