Allow only computing necessary influences in LocalGraph. NFC (#3861)

Some passes need setInfluences but not getInfluences, but were
computing them nonetheless.

This makes e.g. MergeLocals 12% faster. It will also help use LocalGraph
in new passes with less worries about speed.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/passes/MergeLocals.cpp b/src/passes/MergeLocals.cpp
index 2b4b3efea..a55d81cf6 100644
--- a/src/passes/MergeLocals.cpp
+++ b/src/passes/MergeLocals.cpp
@@ -192,7 +192,7 @@ struct MergeLocals
       // the live range unless we are definitely removing a conflict, same
       // logic as before).
       LocalGraph postGraph(func);
-      postGraph.computeInfluences();
+      postGraph.computeSetInfluences();
       for (auto& pair : optimizedToCopy) {
         auto* copy = pair.first;
         auto* trivial = pair.second;