lib/CodeGen/LiveRangeUtils.h

   1 //===-- LiveRangeUtils.h - Live Range modification utilities ----*- C++ -*-===//
   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 contains helper functions to modify live ranges.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_LIB_CODEGEN_LIVERANGEUTILS_H
  14 #define LLVM_LIB_CODEGEN_LIVERANGEUTILS_H
  15
  16 #include "llvm/CodeGen/LiveInterval.h"
  17
  18 namespace llvm {
  19
  20 /// Helper function that distributes live range value numbers and the
  21 /// corresponding segments of a master live range \p LR to a list of newly
  22 /// created live ranges \p SplitLRs. \p VNIClasses maps each value number in \p
  23 /// LR to 0 meaning it should stay or to 1..N meaning it should go to a specific
  24 /// live range in the \p SplitLRs array.
  25 template<typename LiveRangeT, typename EqClassesT>
  26 static void DistributeRange(LiveRangeT &LR, LiveRangeT *SplitLRs[],
  27                             EqClassesT VNIClasses) {
  28   // Move segments to new intervals.
  29   typename LiveRangeT::iterator J = LR.begin(), E = LR.end();
  30   while (J != E && VNIClasses[J->valno->id] == 0)
  31     ++J;
  32   for (typename LiveRangeT::iterator I = J; I != E; ++I) {
  33     if (unsigned eq = VNIClasses[I->valno->id]) {
  34       assert((SplitLRs[eq-1]->empty() || SplitLRs[eq-1]->expiredAt(I->start)) &&
  35              "New intervals should be empty");
  36       SplitLRs[eq-1]->segments.push_back(*I);
  37     } else
  38       *J++ = *I;
  39   }
  40   LR.segments.erase(J, E);
  41
  42   // Transfer VNInfos to their new owners and renumber them.
  43   unsigned j = 0, e = LR.getNumValNums();
  44   while (j != e && VNIClasses[j] == 0)
  45     ++j;
  46   for (unsigned i = j; i != e; ++i) {
  47     VNInfo *VNI = LR.getValNumInfo(i);
  48     if (unsigned eq = VNIClasses[i]) {
  49       VNI->id = SplitLRs[eq-1]->getNumValNums();
  50       SplitLRs[eq-1]->valnos.push_back(VNI);
  51     } else {
  52       VNI->id = j;
  53       LR.valnos[j++] = VNI;
  54     }
  55   }
  56   LR.valnos.resize(j);
  57 }
  58
  59 } // End llvm namespace
  60
  61 #endif