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
18namespace 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.
25template<typename LiveRangeT, typename EqClassesT>
26static 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
62