T11758 testcase help needed

[Edward Z. Yang]

I am not sure if this will work, but how about dumping the assembly and
looking for sign extension?  C-- might be easier!

Excerpts from Alex Dzyoba's message of 2016-07-09 08:25:39 -0400:
> Hi, all!
> 
> I was working on #11758, which is about dropping binutils<2.17 hack, and while
> it was relatively easy to remove the hack itself, I'm not sure how to add a
> test case for it.
> 
> As I understand, after removing the aforementioned hack, native codegen now
> shouldn't generate sign extension. So my question is how to test it? Should it
> be Cmm file that will be tested with `compile_cmp_asm` like memcpy in
> "codeGen/should_gen_asm/memcpy.cmm"? Or should I stick to
> the Haskell test?
> 
> Thanks,
> Alex Dzyoba