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.

llvm-svn: 150226

2 files changed, 3 insertions, 6 deletions

diff --git a/llvm/lib/Target/PTX/PTXRegAlloc.cpp b/llvm/lib/Target/PTX/PTXRegAlloc.cpp
index 2d2d5c30c8c..7fd53752bf6 100644
--- a/llvm/lib/Target/PTX/PTXRegAlloc.cpp
+++ b/llvm/lib/Target/PTX/PTXRegAlloc.cpp
@@ -24,10 +24,7 @@ namespace {
   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 @@ namespace {
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
-      AU.addRequiredID(PHIEliminationID);
-      AU.addRequiredID(TwoAddressInstructionPassID);
       MachineFunctionPass::getAnalysisUsage(AU);
     }
 
diff --git a/llvm/lib/Target/PTX/PTXTargetMachine.cpp b/llvm/lib/Target/PTX/PTXTargetMachine.cpp
index 0432a8bcbd2..aac4555d020 100644
--- a/llvm/lib/Target/PTX/PTXTargetMachine.cpp
+++ b/llvm/lib/Target/PTX/PTXTargetMachine.cpp
@@ -319,6 +319,8 @@ bool PTXPassConfig::addCodeGenPasses(MCContext *&OutContext) {
     printAndVerify("After PreRegAlloc passes");
 
   // Perform register allocation.
+  addPass(PHIEliminationID);
+  addPass(TwoAddressInstructionPassID);
   PM.add(createPTXRegisterAllocator());
   printAndVerify("After Register Allocation");