Readdress r236990, use of static members on a non-static variable.

The TargetRegistry is just a namespace-like class, instantiated in one
place to use a range-based for loop. Instead, expose access to the
registry via a range-based 'targets()' function instead. This makes most
uses a bit awkward/more verbose - but eventually we should just add a
range-based find_if function which will streamline these functions. I'm
happy to mkae them a bit awkward in the interim as encouragement to
improve the algorithms in time.

llvm-svn: 237059
diff --git a/llvm/lib/ExecutionEngine/TargetSelect.cpp b/llvm/lib/ExecutionEngine/TargetSelect.cpp
index e6679cf..57f6e08 100644
--- a/llvm/lib/ExecutionEngine/TargetSelect.cpp
+++ b/llvm/lib/ExecutionEngine/TargetSelect.cpp
@@ -49,21 +49,19 @@
   // Adjust the triple to match what the user requested.
   const Target *TheTarget = nullptr;
   if (!MArch.empty()) {
-    for (TargetRegistry::iterator it = TargetRegistry::begin(),
-           ie = TargetRegistry::end(); it != ie; ++it) {
-      if (MArch == it->getName()) {
-        TheTarget = &*it;
-        break;
-      }
-    }
+    auto I = std::find_if(
+        TargetRegistry::targets().begin(), TargetRegistry::targets().end(),
+        [&](const Target &T) { return MArch == T.getName(); });
 
-    if (!TheTarget) {
+    if (I == TargetRegistry::targets().end()) {
       if (ErrorStr)
         *ErrorStr = "No available targets are compatible with this -march, "
                     "see -version for the available targets.\n";
       return nullptr;
     }
 
+    TheTarget = &*I;
+
     // Adjust the triple to match (if known), otherwise stick with the
     // requested/host triple.
     Triple::ArchType Type = Triple::getArchTypeForLLVMName(MArch);