[PATCH] D29511: [X86]: Don't set a regmask on conditional tail calls (PR31257)

[Michael Kuperstein via Phabricator via llvm-commits]

mkuper added a comment.

What's special about this code (and why I'm reluctant for it to go in) is that we're "lying" :-)  That is, we're pretending an instruction that may clobber registers doesn't. That kind of stuff tends to be brittle.
Also, it's inconsistent - if the reasoning is that a TCRETURN doesn't need to provide a regmask (because which registers a return "clobbers" doesn't matter), then I guess we should fix this by never attaching a mask to any TCRETURN. Then you also won't have the problem of copying it here, since the original TCRETURN won't have one either.

Re 2 - I didn't notice where the regmask was actually coming from! Yes, this makes much more sense. But see above.


https://reviews.llvm.org/D29511