Fix external symbol printing in the AsmPrinter.  Tell the ISel that we
don't support things like memcpy directly.  This allows a handful of the
Shootout programs to work, yay!

llvm-svn: 20939
diff --git a/llvm/lib/Target/PowerPC/PowerPCAsmPrinter.cpp b/llvm/lib/Target/PowerPC/PowerPCAsmPrinter.cpp
index a50a437..025ce98 100644
--- a/llvm/lib/Target/PowerPC/PowerPCAsmPrinter.cpp
+++ b/llvm/lib/Target/PowerPC/PowerPCAsmPrinter.cpp
@@ -349,7 +349,13 @@
     return;
 
   case MachineOperand::MO_ExternalSymbol:
-    O << MO.getSymbolName();
+    if (IsCallOp) {
+      std::string Name(GlobalPrefix); Name += MO.getSymbolName();
+      FnStubs.insert(Name);
+      O << "L" << Name << "$stub";
+      return;
+    }
+    O << GlobalPrefix << MO.getSymbolName();
     return;
 
   case MachineOperand::MO_GlobalAddress: {