[llvm] [StaleProfileMatching] Use only profile anchor size for similarity calculation (PR #126783)

[Lei Wang via llvm-commits]

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@@ -23,7 +23,7 @@ using namespace sampleprof;
 #define DEBUG_TYPE "sample-profile-matcher"
 
 static cl::opt<unsigned> FuncProfileSimilarityThreshold(
-    "func-profile-similarity-threshold", cl::Hidden, cl::init(80),
+    "func-profile-similarity-threshold", cl::Hidden, cl::init(70),
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wlei-llvm wrote:

This is just from my observation, may not be accurate. I observed that there were many false negatives(we missed the good match). Recalling that it's under the LCS frame, the matching scope is narrowed, it's very likely to have a good match. So I feel overall threshold is a bit too high, so try to lower it a bit.

https://github.com/llvm/llvm-project/pull/126783