Index: clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
===================================================================
--- clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
+++ clang/lib/StaticAnalyzer/Core/CheckerContext.cpp
@@ -55,8 +55,29 @@
     if (Name.empty())
       return true;
     StringRef BName = FD->getASTContext().BuiltinInfo.getName(BId);
-    if (BName.contains(Name))
-      return true;
+    size_t start = BName.find(Name);
+    if (start != StringRef::npos) {
+      // Accept exact match.
+      if (BName.size() == Name.size())
+        return true;
+
+      //    v-- match starts here
+      // ...xxxxx...
+      //   _xxxxx_
+      //   ^     ^ lookbehind and lookahead characters
+
+      const auto MatchPredecessor = [=]() -> bool {
+        return start <= 0 || !llvm::isAlpha(BName[start - 1]);
+      };
+      const auto MatchSuccessor = [=]() -> bool {
+        std::size_t LookbehindPlace = start + Name.size();
+        return LookbehindPlace >= BName.size() ||
+               !llvm::isAlpha(BName[LookbehindPlace]);
+      };
+
+      if (MatchPredecessor() && MatchSuccessor())
+        return true;
+    }
   }
 
   const IdentifierInfo *II = FD->getIdentifier();
Index: clang/unittests/StaticAnalyzer/CallDescriptionTest.cpp
===================================================================
--- clang/unittests/StaticAnalyzer/CallDescriptionTest.cpp
+++ clang/unittests/StaticAnalyzer/CallDescriptionTest.cpp
@@ -487,6 +487,60 @@
       "  __builtin___memset_chk(&x, 0, sizeof(x),"
       "                         __builtin_object_size(&x, 0));"
       "}"));
+
+  {
+    SCOPED_TRACE("multiple similar builtins");
+    EXPECT_TRUE(tooling::runToolOnCode(
+        std::unique_ptr<FrontendAction>(new CallDescriptionAction<>(
+            {{{CDF_MaybeBuiltin, "memcpy", 3}, false},
+             {{CDF_MaybeBuiltin, "wmemcpy", 3}, true}})),
+        R"(void foo(wchar_t *x, wchar_t *y) {
+            __builtin_wmemcpy(x, y, sizeof(wchar_t));
+          })"));
+  }
+  {
+    SCOPED_TRACE("multiple similar builtins reversed order");
+    EXPECT_TRUE(tooling::runToolOnCode(
+        std::unique_ptr<FrontendAction>(new CallDescriptionAction<>(
+            {{{CDF_MaybeBuiltin, "wmemcpy", 3}, true},
+             {{CDF_MaybeBuiltin, "memcpy", 3}, false}})),
+        R"(void foo(wchar_t *x, wchar_t *y) {
+            __builtin_wmemcpy(x, y, sizeof(wchar_t));
+          })"));
+  }
+  {
+    SCOPED_TRACE("lookbehind and lookahead mismatches");
+    EXPECT_TRUE(tooling::runToolOnCode(
+        std::unique_ptr<FrontendAction>(
+            new CallDescriptionAction<>({{{CDF_MaybeBuiltin, "func"}, false}})),
+        R"(
+          void funcXXX();
+          void XXXfunc();
+          void XXXfuncXXX();
+          void test() {
+            funcXXX();
+            XXXfunc();
+            XXXfuncXXX();
+          })"));
+  }
+  {
+    SCOPED_TRACE("lookbehind and lookahead matches");
+    EXPECT_TRUE(tooling::runToolOnCode(
+        std::unique_ptr<FrontendAction>(
+            new CallDescriptionAction<>({{{CDF_MaybeBuiltin, "func"}, true}})),
+        R"(
+          void func();
+          void func_XXX();
+          void XXX_func();
+          void XXX_func_XXX();
+
+          void test() {
+            func(); // exact match
+            func_XXX();
+            XXX_func();
+            XXX_func_XXX();
+          })"));
+  }
 }
 
 } // namespace