Apply most suggestions of clang-tidy's performance-unnecessary-value-param

Avoids unnecessary copies. All changes audited & pass tests with asan.
No functional change intended.

llvm-svn: 272190
diff --git a/llvm/lib/Analysis/TargetLibraryInfo.cpp b/llvm/lib/Analysis/TargetLibraryInfo.cpp
index 925e7ce..68b0764 100644
--- a/llvm/lib/Analysis/TargetLibraryInfo.cpp
+++ b/llvm/lib/Analysis/TargetLibraryInfo.cpp
@@ -1133,7 +1133,7 @@
       lookupInfoImpl(Triple(F.getParent()->getTargetTriple())));
 }
 
-TargetLibraryInfoImpl &TargetLibraryAnalysis::lookupInfoImpl(Triple T) {
+TargetLibraryInfoImpl &TargetLibraryAnalysis::lookupInfoImpl(const Triple &T) {
   std::unique_ptr<TargetLibraryInfoImpl> &Impl =
       Impls[T.normalize()];
   if (!Impl)