[ADT] Use DenseMap::contains in EquivalenceClasses.h (NFC)

[kazutakahirata]

While I am at it, this patch adds [[nodiscard]].

[llvmbot]

@llvm/pr-subscribers-llvm-adt

Author: Kazu Hirata (kazutakahirata)

Changes

While I am at it, this patch adds [[nodiscard]].

---

Full diff: https://github.com/llvm/llvm-project/pull/161120.diff

1 Files Affected:

• (modified) llvm/include/llvm/ADT/EquivalenceClasses.h (+2-2)

diff --git a/llvm/include/llvm/ADT/EquivalenceClasses.h b/llvm/include/llvm/ADT/EquivalenceClasses.h
index 1a2331c1a0322..7df0d1557af87 100644
--- a/llvm/include/llvm/ADT/EquivalenceClasses.h
+++ b/llvm/include/llvm/ADT/EquivalenceClasses.h
@@ -180,8 +180,8 @@ template <class ElemTy> class EquivalenceClasses {
   }
 
   /// Returns true if \p V is contained an equivalence class.
-  bool contains(const ElemTy &V) const {
-    return TheMapping.find(V) != TheMapping.end();
+  [[nodiscard]] bool contains(const ElemTy &V) const {
+    return TheMapping.contains(V);
   }
 
   /// getLeaderValue - Return the leader for the specified value that is in the