llvm/tools/llvm-reduce/deltas/ReduceVirtualRegisters.cpp

   1 //===- ReduceVirtualRegisters.cpp - Specialized Delta Pass ----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file implements a function which calls the Generic Delta pass in order
  10 // to simplify virtual registers in MIR.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "ReduceVirtualRegisters.h"
  15 #include "Delta.h"
  16 #include "llvm/CodeGen/MachineModuleInfo.h"
  17 #include "llvm/CodeGen/MachineRegisterInfo.h"
  18
  19 using namespace llvm;
  20
  21 static void dropRegisterHintsFromFunction(Oracle &O, MachineFunction &MF) {
  22   MachineRegisterInfo &MRI = MF.getRegInfo();
  23   for (unsigned I = 0, E = MRI.getNumVirtRegs(); I != E; ++I) {
  24     Register Reg = Register::index2VirtReg(I);
  25
  26     const std::pair<unsigned, SmallVector<Register, 4>> &Hints =
  27         MRI.getRegAllocationHints(Reg);
  28     if (Hints.second.empty())
  29       continue;
  30
  31     if (!O.shouldKeep())
  32       MRI.clearSimpleHint(Reg);
  33   }
  34 }
  35
  36 static void dropRegisterHintsFromFunctions(Oracle &O,
  37                                            ReducerWorkItem &WorkItem) {
  38   for (const Function &F : WorkItem.getModule()) {
  39     if (auto *MF = WorkItem.MMI->getMachineFunction(F))
  40       dropRegisterHintsFromFunction(O, *MF);
  41   }
  42 }
  43
  44 void llvm::reduceVirtualRegisterHintsDeltaPass(TestRunner &Test) {
  45   runDeltaPass(Test, dropRegisterHintsFromFunctions,
  46                "Reducing virtual register hints from functions");
  47 }