PTX: Add new PTX-specific register allocator that keeps virtual registers

instead of allocating physical registers.

This is part of a work-in-progress overhaul of the PTX register allocation scheme.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140305 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 61 insertions, 0 deletions

diff --git a/lib/Target/PTX/CMakeLists.txt b/lib/Target/PTX/CMakeLists.txt
index bfbbe87281..bee8ab781c 100644
--- a/lib/Target/PTX/CMakeLists.txt
+++ b/lib/Target/PTX/CMakeLists.txt
@@ -16,6 +16,7 @@ add_llvm_target(PTXCodeGen
   PTXFrameLowering.cpp
   PTXMCAsmStreamer.cpp
   PTXMFInfoExtract.cpp
+  PTXRegAlloc.cpp
   PTXRegisterInfo.cpp
   PTXSubtarget.cpp
   PTXTargetMachine.cpp
diff --git a/lib/Target/PTX/PTX.h b/lib/Target/PTX/PTX.h
index 28cab2429c..ddd9e24126 100644
--- a/lib/Target/PTX/PTX.h
+++ b/lib/Target/PTX/PTX.h
@@ -43,6 +43,8 @@ namespace llvm {
   FunctionPass *createPTXMFInfoExtract(PTXTargetMachine &TM,
                                        CodeGenOpt::Level OptLevel);
 
+  FunctionPass *createPTXRegisterAllocator();
+
 } // namespace llvm;
 
 #endif // PTX_H
diff --git a/lib/Target/PTX/PTXRegAlloc.cpp b/lib/Target/PTX/PTXRegAlloc.cpp
new file mode 100644
index 0000000000..2d2d5c30c8
--- /dev/null
+++ b/lib/Target/PTX/PTXRegAlloc.cpp
@@ -0,0 +1,58 @@
+//===-- PTXRegAlloc.cpp - PTX Register Allocator --------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a register allocator for PTX code.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "ptx-reg-alloc"
+
+#include "PTX.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/RegAllocRegistry.h"
+
+using namespace llvm;
+
+namespace {
+  // Special register allocator for PTX.
+  class PTXRegAlloc : public MachineFunctionPass {
+  public:
+    static char ID;
+    PTXRegAlloc() : MachineFunctionPass(ID) {
+      initializePHIEliminationPass(*PassRegistry::getPassRegistry());
+      initializeTwoAddressInstructionPassPass(*PassRegistry::getPassRegistry());
+    }
+
+    virtual const char* getPassName() const {
+      return "PTX Register Allocator";
+    }
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesCFG();
+      AU.addRequiredID(PHIEliminationID);
+      AU.addRequiredID(TwoAddressInstructionPassID);
+      MachineFunctionPass::getAnalysisUsage(AU);
+    }
+
+    virtual bool runOnMachineFunction(MachineFunction &MF) {
+      // We do not actually do anything (at least not yet).
+      return false;
+    }
+  };
+
+  char PTXRegAlloc::ID = 0;
+
+  static RegisterRegAlloc
+    ptxRegAlloc("ptx", "PTX register allocator", createPTXRegisterAllocator);
+}
+
+FunctionPass *llvm::createPTXRegisterAllocator() {
+  return new PTXRegAlloc();
+}
+