[llvm] [ICP] Add a few tunings to indirect-call-promotion (PR #149892)

[via llvm-commits]

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@@ -80,6 +80,18 @@ static cl::opt<unsigned>
     ICPCSSkip("icp-csskip", cl::init(0), cl::Hidden,
               cl::desc("Skip Callsite up to this number for this compilation"));
 
+// ICP the candidate function even when only a declaration is present.
+static cl::opt<bool>
+    ICPAllowDeclOnly("icp-allow-decl-only", cl::init(true), cl::Hidden,
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xur-llvm wrote:

We do want the behavior change, right?

https://github.com/llvm/llvm-project/pull/149892