[PATCH] D13826: [Bitcode] Limit bits used for CallingConv::ID in Function, update tests

[Duncan P. N. Exon Smith via llvm-commits]

> On 2015-Oct-16, at 12:56, Vedant Kumar <vsk at apple.com> wrote:
> 
> vsk created this revision.
> vsk added reviewers: dblaikie, dexonsmith.
> vsk added a subscriber: llvm-commits.
> 
> - Use 10 bits to represent calling convention ID's instead of 13.
> - Update the bitcode compatibility tests to reflect this change.
> 
> We currently implement about 80 calling conventions. This change lowers the cap to 1023 CC's (from 8191). This gives us back reserve bits in Function's subclass data field, which I plan on using soon.

Vedant and I already talked about this in person, so it makes
sense to me... but I don't really know much about calling
conventions.  I'd like to hear from others.

Is there any reason we'd need more than 1K calling conventions?

> I've also fixed syntax errors in the compatibility tests caused by accidental 3.6 -> 3.8 IR conversion.

These changes should be in a separate NFC commit.  The fix is
obvious, so it should just be post-commit.  (LGTM anyway.)

> 
> http://reviews.llvm.org/D13826
> 
> Files:
>  include/llvm/IR/Function.h
>  test/Bitcode/compatibility-3.6.ll
>  test/Bitcode/compatibility-3.6.ll.bc
>  test/Bitcode/compatibility-3.7.ll
>  test/Bitcode/compatibility-3.7.ll.bc
>  test/Bitcode/compatibility.ll
>  test/Bitcode/tailcall.ll
> 
> <D13826.37625.patch>