MC: Label definitions are permitted after .set directives

.set directives may be overridden by other .set directives as well as
label definitions.

This fixes PR22019.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224811 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/AsmPrinter/AsmPrinter.cpp

@@ -541,6 +541,8 @@ void AsmPrinter::EmitFunctionHeader() {
 /// EmitFunctionEntryLabel - Emit the label that is the entrypoint for the
 /// function.  This can be overridden by targets as required to do custom stuff.
 void AsmPrinter::EmitFunctionEntryLabel() {
+  CurrentFnSym->redefineIfPossible();
+
   // The function label could have already been emitted if two symbols end up
   // conflicting due to asm renaming.  Detect this and emit an error.
   if (CurrentFnSym->isUndefined())