[llvm] [Preinliner] Always inline when SizeCost is zero (PR #88785)

[via llvm-commits]

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@@ -152,6 +152,9 @@ uint32_t CSPreInliner::getFuncSize(const ContextTrieNode *ContextNode) {
 }
 
 bool CSPreInliner::shouldInline(ProfiledInlineCandidate &Candidate) {
+  if (Candidate.SizeCost == 0)
+    return true;
+
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WenleiHe wrote:

+1. We probably don't want the special case. Either have +1 for cold path too, or remove +1 for hot path, and change to <= in the end.

https://github.com/llvm/llvm-project/pull/88785