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

1 files changed, 3 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/RegAllocFast.cpp b/llvm/lib/CodeGen/RegAllocFast.cpp
index a54785d..4724ca2 100644
--- a/llvm/lib/CodeGen/RegAllocFast.cpp
+++ b/llvm/lib/CodeGen/RegAllocFast.cpp
@@ -49,10 +49,7 @@ namespace {
   public:
     static char ID;
     RAFast() : MachineFunctionPass(ID), StackSlotForVirtReg(-1),
-               isBulkSpilling(false) {
-      initializePHIEliminationPass(*PassRegistry::getPassRegistry());
-      initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
-    }
+               isBulkSpilling(false) {}
   private:
     const TargetMachine *TM;
     MachineFunction *MF;
@@ -137,8 +134,6 @@ namespace {
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
       AU.setPreservesCFG();
-      AU.addRequiredID(PHIEliminationID);
-      AU.addRequiredID(TwoAddressInstructionPassID);
       MachineFunctionPass::getAnalysisUsage(AU);
     }
 
@@ -1089,6 +1084,8 @@ bool RAFast::runOnMachineFunction(MachineFunction &Fn) {
   RegClassInfo.runOnMachineFunction(Fn);
   UsedInInstr.resize(TRI->getNumRegs());
 
+  assert(!MRI->isSSA() && "regalloc requires leaving SSA");
+
   // initialize the virtual->physical register map to have a 'null'
   // mapping for all virtual registers
   StackSlotForVirtReg.resize(MRI->getNumVirtRegs());