lib/CodeGen/LiveRangeUtils.h

   1 //===-- LiveRangeUtils.h - Live Range modification utilities ----*- C++ -*-===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 /// This file contains helper functions to modify live ranges.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #ifndef LLVM_LIB_CODEGEN_LIVERANGEUTILS_H
  15 #define LLVM_LIB_CODEGEN_LIVERANGEUTILS_H
  16
  17 #include "llvm/CodeGen/LiveInterval.h"
  18
  19 namespace llvm {
  20
  21 /// Helper function that distributes live range value numbers and the
  22 /// corresponding segments of a master live range \p LR to a list of newly
  23 /// created live ranges \p SplitLRs. \p VNIClasses maps each value number in \p
  24 /// LR to 0 meaning it should stay or to 1..N meaning it should go to a specific
  25 /// live range in the \p SplitLRs array.
  26 template<typename LiveRangeT, typename EqClassesT>
  27 static void DistributeRange(LiveRangeT &LR, LiveRangeT *SplitLRs[],
  28                             EqClassesT VNIClasses) {
  29   // Move segments to new intervals.
  30   typename LiveRangeT::iterator J = LR.begin(), E = LR.end();
  31   while (J != E && VNIClasses[J->valno->id] == 0)
  32     ++J;
  33   for (typename LiveRangeT::iterator I = J; I != E; ++I) {
  34     if (unsigned eq = VNIClasses[I->valno->id]) {
  35       assert((SplitLRs[eq-1]->empty() || SplitLRs[eq-1]->expiredAt(I->start)) &&
  36              "New intervals should be empty");
  37       SplitLRs[eq-1]->segments.push_back(*I);
  38     } else
  39       *J++ = *I;
  40   }
  41   LR.segments.erase(J, E);
  42
  43   // Transfer VNInfos to their new owners and renumber them.
  44   unsigned j = 0, e = LR.getNumValNums();
  45   while (j != e && VNIClasses[j] == 0)
  46     ++j;
  47   for (unsigned i = j; i != e; ++i) {
  48     VNInfo *VNI = LR.getValNumInfo(i);
  49     if (unsigned eq = VNIClasses[i]) {
  50       VNI->id = SplitLRs[eq-1]->getNumValNums();
  51       SplitLRs[eq-1]->valnos.push_back(VNI);
  52     } else {
  53       VNI->id = j;
  54       LR.valnos[j++] = VNI;
  55     }
  56   }
  57   LR.valnos.resize(j);
  58 }
  59
  60 } // End llvm namespace
  61
  62 #endif