RegAlloc superpass: includes phi elimination, coalescing, and scheduling.

Creates a configurable regalloc pipeline.

Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa.

When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>.

CodeGen transformation passes are never "required" as an analysis

ProcessImplicitDefs does not require LiveVariables.

We have a plan to massively simplify some of the early passes within the regalloc superpass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150226 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/PTX/PTXRegAlloc.cpp b/lib/Target/PTX/PTXRegAlloc.cpp
index 2d2d5c3..7fd5375 100644
--- a/lib/Target/PTX/PTXRegAlloc.cpp
+++ b/lib/Target/PTX/PTXRegAlloc.cpp
@@ -24,10 +24,7 @@
   class PTXRegAlloc : public MachineFunctionPass {
   public:
     static char ID;
-    PTXRegAlloc() : MachineFunctionPass(ID) {
-      initializePHIEliminationPass(*PassRegistry::getPassRegistry());
-      initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
-    }
+    PTXRegAlloc() : MachineFunctionPass(ID) {}
 
     virtual const char* getPassName() const {
       return "PTX Register Allocator";
@@ -35,8 +32,6 @@
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
-      AU.addRequiredID(PHIEliminationID);
-      AU.addRequiredID(TwoAddressInstructionPassID);
       MachineFunctionPass::getAnalysisUsage(AU);
     }