[PATCH] D40893: [PowerPC] fix a bug in TCO eligibility check

[Hal Finkel via Phabricator via llvm-commits]

hfinkel added a comment.

In https://reviews.llvm.org/D40893#952121, @inouehrs wrote:

> > Can you also update the patch description? One inline request as well. You can also handle the inline request as a separate commit.
>
> I updated the description.
>
> About the URL in the comment, it is an example of a case where GCC can do sibling call optimization even with a byval parameter rather tan an additional explanation on why this is a workaround; the example is too large to embed in a comment.
>  How about changing `See: https://...` to `GCC can do such sibling call optimization such as https://...` or just remove `See: https://...`? Any preference?
>  Anyway I like to touch up this comment later in another patch.


What value is the link adding? Is it just the test case? If so:

1. The test case is actually short enough for a comment, and
2. You could generate IR from that test case and add it (with a FIXME note in the test case that we can do better).



================
Comment at: lib/Target/PowerPC/PPCISelLowering.cpp:4400
                                     CallingConv::ID CalleeCC) {
-  // Tail or Sibling call optimization (TCO/SCO) needs callee and caller to
-  // have the same calling convention.
-  if (CallerCC != CalleeCC)
+  // tail calls are possible with fastcc and ccc.
+  auto isTailCallableCC  = [] (CallingConv::ID CC){
----------------
tail -> Tail


https://reviews.llvm.org/D40893