Partial merge of r293110 into the 4.0 branch

Avoid printing optimization remarks from llc unless they are enabled.

Fixes http://llvm.org/PR32184

git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_40@299409 91177308-0d34-0410-b5e6-96231b3b80d8

Author: tstellar

tools/llc/llc.cpp

@@ -233,6 +233,10 @@ static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context) {
   if (DI.getSeverity() == DS_Error)
     *HasError = true;
 
+  if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
+    if (!Remark->isEnabled())
+      return;
+
   DiagnosticPrinterRawOStream DP(errs());
   errs() << LLVMContext::getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
   DI.print(DP);