Change the PassManager from a reference to a pointer.

The TargetPassManager's default constructor wants to initialize the PassManager
to 'null'. But it's illegal to bind a null reference to a null l-value. Make the
ivar a pointer instead.
PR12468


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155902 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PowerPC/PPCTargetMachine.cpp b/lib/Target/PowerPC/PPCTargetMachine.cpp
index d113976..50f3db8 100644
--- a/lib/Target/PowerPC/PPCTargetMachine.cpp
+++ b/lib/Target/PowerPC/PPCTargetMachine.cpp
@@ -98,13 +98,13 @@
 
 bool PPCPassConfig::addInstSelector() {
   // Install an instruction selector.
-  PM.add(createPPCISelDag(getPPCTargetMachine()));
+  PM->add(createPPCISelDag(getPPCTargetMachine()));
   return false;
 }
 
 bool PPCPassConfig::addPreEmitPass() {
   // Must run branch selection immediately preceding the asm printer.
-  PM.add(createPPCBranchSelectionPass());
+  PM->add(createPPCBranchSelectionPass());
   return false;
 }