[llvm] r309330 - [ConstantFolder] Don't try to fold gep when the idx is a vector.

[David Majnemer via llvm-commits]

Yes, let's merge it.

On Mon, Jul 31, 2017 at 10:34 AM, Hans Wennborg <hans at chromium.org> wrote:

> On Thu, Jul 27, 2017 at 3:23 PM, Davide Italiano <davide at freebsd.org>
> wrote:
> > On Thu, Jul 27, 2017 at 3:20 PM, Davide Italiano via llvm-commits
> > <llvm-commits at lists.llvm.org> wrote:
> >> Author: davide
> >> Date: Thu Jul 27 15:20:44 2017
> >> New Revision: 309330
> >>
> >> URL: http://llvm.org/viewvc/llvm-project?rev=309330&view=rev
> >> Log:
> >> [ConstantFolder] Don't try to fold gep when the idx is a vector.
> >>
> >> The code in ConstantFoldGetElementPtr() assumes integers, and
> >> therefore it crashes trying to get the integer bidwith of a vector
> >> type (in this case <4 x i32>. I just changed the code to prevent
> >> the folding in case of vectors and I didn't bother to generalize
> >> as this doesn't seem to me something that really happens in
> >> practice, but I'm willing to change the patch if you think
> >> it's worth it.
> >> This is hard to trigger from -instsimplify or -instcombine
> >> only as the second instruction is dead, so the test uses loop-unroll.
> >>
> >
> > Hans, David, can we consider merging this to 5.0?
>
> David: what do you think?
>
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