[PATCH] D147954: [SimplifyCFG]Prevent premature simplification of indirect callsites with profile data

[Mingming Liu via Phabricator via llvm-commits]

mingmingl planned changes to this revision.
mingmingl added a comment.

In D147954#4276844 <https://reviews.llvm.org/D147954#4276844>, @nikic wrote:

> Could you please start by implementing metadata merging, and then return to this patch only if strictly necessary? I'd rather not have another SimplifyCFG option for such a niche use case, if it's possible to get most of the benefit via standard metadata merging.

(quick reply to describe the plan) okay, let me implement something as described and see how it works for this use case

1. do metadata merging for direct callsites 2) conservatively not hoisting/sinking indirect callsites for indirect callsites if `!prof` presents -> indirect-call-promotion pass will clear `!prof` for indirect-callsite (since there are no other uses of  this type of value profiles) so the SimplifyCFG pass after indirect-call-promotion should be able to do a full cleanup if the indirect-call is still in the IR but not speculatively devirtualized.


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https://reviews.llvm.org/D147954