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When a live range splits into multiple connected components, we would arbitrarily assign <undef> uses to component 0. This is wrong when the use is tied to a def that gets assigned to a different component: %vreg69<def> = ADD8ri %vreg68<undef>, 1 The use and def must get the same virtual register. Fix this by assigning <undef> uses to the same component as the value defined by the instruction, if any: %vreg69<def> = ADD8ri %vreg69<undef>, 1 This fixes PR13402. The PR has a test case which I am not including because it is unlikely to keep exposing this behavior in the future. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160739 91177308-0d34-0410-b5e6-96231b3b80d8
870 lines
28 KiB
C++
870 lines
28 KiB
C++
//===-- LiveInterval.cpp - Live Interval Representation -------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the LiveRange and LiveInterval classes. Given some
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// numbering of each the machine instructions an interval [i, j) is said to be a
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// live interval for register v if there is no instruction with number j' > j
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// such that v is live at j' and there is no instruction with number i' < i such
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// that v is live at i'. In this implementation intervals can have holes,
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// i.e. an interval might look like [1,20), [50,65), [1000,1001). Each
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// individual range is represented as an instance of LiveRange, and the whole
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// interval is represented as an instance of LiveInterval.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/CodeGen/LiveInterval.h"
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#include "llvm/CodeGen/LiveIntervalAnalysis.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetRegisterInfo.h"
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#include <algorithm>
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using namespace llvm;
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LiveInterval::iterator LiveInterval::find(SlotIndex Pos) {
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// This algorithm is basically std::upper_bound.
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// Unfortunately, std::upper_bound cannot be used with mixed types until we
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// adopt C++0x. Many libraries can do it, but not all.
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if (empty() || Pos >= endIndex())
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return end();
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iterator I = begin();
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size_t Len = ranges.size();
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do {
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size_t Mid = Len >> 1;
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if (Pos < I[Mid].end)
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Len = Mid;
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else
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I += Mid + 1, Len -= Mid + 1;
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} while (Len);
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return I;
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}
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VNInfo *LiveInterval::createDeadDef(SlotIndex Def,
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VNInfo::Allocator &VNInfoAllocator) {
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assert(!Def.isDead() && "Cannot define a value at the dead slot");
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iterator I = find(Def);
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if (I == end()) {
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VNInfo *VNI = getNextValue(Def, VNInfoAllocator);
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ranges.push_back(LiveRange(Def, Def.getDeadSlot(), VNI));
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return VNI;
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}
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if (SlotIndex::isSameInstr(Def, I->start)) {
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assert(I->start == Def && "Cannot insert def, already live");
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assert(I->valno->def == Def && "Inconsistent existing value def");
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return I->valno;
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}
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assert(SlotIndex::isEarlierInstr(Def, I->start) && "Already live at def");
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VNInfo *VNI = getNextValue(Def, VNInfoAllocator);
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ranges.insert(I, LiveRange(Def, Def.getDeadSlot(), VNI));
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return VNI;
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}
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/// killedInRange - Return true if the interval has kills in [Start,End).
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bool LiveInterval::killedInRange(SlotIndex Start, SlotIndex End) const {
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Ranges::const_iterator r =
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std::lower_bound(ranges.begin(), ranges.end(), End);
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// Now r points to the first interval with start >= End, or ranges.end().
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if (r == ranges.begin())
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return false;
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--r;
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// Now r points to the last interval with end <= End.
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// r->end is the kill point.
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return r->end >= Start && r->end < End;
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}
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// overlaps - Return true if the intersection of the two live intervals is
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// not empty.
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//
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// An example for overlaps():
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//
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// 0: A = ...
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// 4: B = ...
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// 8: C = A + B ;; last use of A
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//
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// The live intervals should look like:
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//
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// A = [3, 11)
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// B = [7, x)
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// C = [11, y)
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//
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// A->overlaps(C) should return false since we want to be able to join
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// A and C.
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//
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bool LiveInterval::overlapsFrom(const LiveInterval& other,
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const_iterator StartPos) const {
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assert(!empty() && "empty interval");
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const_iterator i = begin();
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const_iterator ie = end();
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const_iterator j = StartPos;
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const_iterator je = other.end();
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assert((StartPos->start <= i->start || StartPos == other.begin()) &&
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StartPos != other.end() && "Bogus start position hint!");
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if (i->start < j->start) {
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i = std::upper_bound(i, ie, j->start);
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if (i != ranges.begin()) --i;
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} else if (j->start < i->start) {
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++StartPos;
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if (StartPos != other.end() && StartPos->start <= i->start) {
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assert(StartPos < other.end() && i < end());
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j = std::upper_bound(j, je, i->start);
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if (j != other.ranges.begin()) --j;
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}
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} else {
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return true;
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}
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if (j == je) return false;
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while (i != ie) {
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if (i->start > j->start) {
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std::swap(i, j);
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std::swap(ie, je);
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}
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if (i->end > j->start)
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return true;
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++i;
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}
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return false;
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}
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/// overlaps - Return true if the live interval overlaps a range specified
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/// by [Start, End).
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bool LiveInterval::overlaps(SlotIndex Start, SlotIndex End) const {
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assert(Start < End && "Invalid range");
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const_iterator I = std::lower_bound(begin(), end(), End);
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return I != begin() && (--I)->end > Start;
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}
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/// ValNo is dead, remove it. If it is the largest value number, just nuke it
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/// (and any other deleted values neighboring it), otherwise mark it as ~1U so
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/// it can be nuked later.
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void LiveInterval::markValNoForDeletion(VNInfo *ValNo) {
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if (ValNo->id == getNumValNums()-1) {
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do {
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valnos.pop_back();
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} while (!valnos.empty() && valnos.back()->isUnused());
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} else {
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ValNo->setIsUnused(true);
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}
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}
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/// RenumberValues - Renumber all values in order of appearance and delete the
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/// remaining unused values.
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void LiveInterval::RenumberValues(LiveIntervals &lis) {
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SmallPtrSet<VNInfo*, 8> Seen;
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valnos.clear();
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for (const_iterator I = begin(), E = end(); I != E; ++I) {
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VNInfo *VNI = I->valno;
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if (!Seen.insert(VNI))
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continue;
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assert(!VNI->isUnused() && "Unused valno used by live range");
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VNI->id = (unsigned)valnos.size();
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valnos.push_back(VNI);
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}
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}
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/// extendIntervalEndTo - This method is used when we want to extend the range
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/// specified by I to end at the specified endpoint. To do this, we should
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/// merge and eliminate all ranges that this will overlap with. The iterator is
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/// not invalidated.
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void LiveInterval::extendIntervalEndTo(Ranges::iterator I, SlotIndex NewEnd) {
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assert(I != ranges.end() && "Not a valid interval!");
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VNInfo *ValNo = I->valno;
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// Search for the first interval that we can't merge with.
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Ranges::iterator MergeTo = llvm::next(I);
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for (; MergeTo != ranges.end() && NewEnd >= MergeTo->end; ++MergeTo) {
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assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
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}
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// If NewEnd was in the middle of an interval, make sure to get its endpoint.
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I->end = std::max(NewEnd, prior(MergeTo)->end);
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// If the newly formed range now touches the range after it and if they have
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// the same value number, merge the two ranges into one range.
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if (MergeTo != ranges.end() && MergeTo->start <= I->end &&
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MergeTo->valno == ValNo) {
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I->end = MergeTo->end;
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++MergeTo;
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}
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// Erase any dead ranges.
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ranges.erase(llvm::next(I), MergeTo);
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}
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/// extendIntervalStartTo - This method is used when we want to extend the range
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/// specified by I to start at the specified endpoint. To do this, we should
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/// merge and eliminate all ranges that this will overlap with.
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LiveInterval::Ranges::iterator
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LiveInterval::extendIntervalStartTo(Ranges::iterator I, SlotIndex NewStart) {
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assert(I != ranges.end() && "Not a valid interval!");
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VNInfo *ValNo = I->valno;
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// Search for the first interval that we can't merge with.
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Ranges::iterator MergeTo = I;
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do {
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if (MergeTo == ranges.begin()) {
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I->start = NewStart;
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ranges.erase(MergeTo, I);
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return I;
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}
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assert(MergeTo->valno == ValNo && "Cannot merge with differing values!");
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--MergeTo;
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} while (NewStart <= MergeTo->start);
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// If we start in the middle of another interval, just delete a range and
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// extend that interval.
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if (MergeTo->end >= NewStart && MergeTo->valno == ValNo) {
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MergeTo->end = I->end;
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} else {
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// Otherwise, extend the interval right after.
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++MergeTo;
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MergeTo->start = NewStart;
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MergeTo->end = I->end;
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}
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ranges.erase(llvm::next(MergeTo), llvm::next(I));
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return MergeTo;
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}
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LiveInterval::iterator
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LiveInterval::addRangeFrom(LiveRange LR, iterator From) {
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SlotIndex Start = LR.start, End = LR.end;
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iterator it = std::upper_bound(From, ranges.end(), Start);
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// If the inserted interval starts in the middle or right at the end of
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// another interval, just extend that interval to contain the range of LR.
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if (it != ranges.begin()) {
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iterator B = prior(it);
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if (LR.valno == B->valno) {
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if (B->start <= Start && B->end >= Start) {
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extendIntervalEndTo(B, End);
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return B;
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}
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} else {
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// Check to make sure that we are not overlapping two live ranges with
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// different valno's.
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assert(B->end <= Start &&
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"Cannot overlap two LiveRanges with differing ValID's"
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" (did you def the same reg twice in a MachineInstr?)");
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}
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}
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// Otherwise, if this range ends in the middle of, or right next to, another
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// interval, merge it into that interval.
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if (it != ranges.end()) {
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if (LR.valno == it->valno) {
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if (it->start <= End) {
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it = extendIntervalStartTo(it, Start);
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// If LR is a complete superset of an interval, we may need to grow its
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// endpoint as well.
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if (End > it->end)
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extendIntervalEndTo(it, End);
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return it;
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}
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} else {
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// Check to make sure that we are not overlapping two live ranges with
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// different valno's.
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assert(it->start >= End &&
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"Cannot overlap two LiveRanges with differing ValID's");
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}
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}
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// Otherwise, this is just a new range that doesn't interact with anything.
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// Insert it.
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return ranges.insert(it, LR);
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}
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/// extendInBlock - If this interval is live before Kill in the basic
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/// block that starts at StartIdx, extend it to be live up to Kill and return
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/// the value. If there is no live range before Kill, return NULL.
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VNInfo *LiveInterval::extendInBlock(SlotIndex StartIdx, SlotIndex Kill) {
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if (empty())
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return 0;
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iterator I = std::upper_bound(begin(), end(), Kill.getPrevSlot());
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if (I == begin())
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return 0;
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--I;
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if (I->end <= StartIdx)
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return 0;
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if (I->end < Kill)
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extendIntervalEndTo(I, Kill);
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return I->valno;
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}
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/// removeRange - Remove the specified range from this interval. Note that
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/// the range must be in a single LiveRange in its entirety.
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void LiveInterval::removeRange(SlotIndex Start, SlotIndex End,
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bool RemoveDeadValNo) {
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// Find the LiveRange containing this span.
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Ranges::iterator I = find(Start);
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assert(I != ranges.end() && "Range is not in interval!");
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assert(I->containsRange(Start, End) && "Range is not entirely in interval!");
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// If the span we are removing is at the start of the LiveRange, adjust it.
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VNInfo *ValNo = I->valno;
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if (I->start == Start) {
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if (I->end == End) {
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if (RemoveDeadValNo) {
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// Check if val# is dead.
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bool isDead = true;
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for (const_iterator II = begin(), EE = end(); II != EE; ++II)
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if (II != I && II->valno == ValNo) {
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isDead = false;
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break;
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}
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if (isDead) {
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// Now that ValNo is dead, remove it.
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markValNoForDeletion(ValNo);
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}
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}
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ranges.erase(I); // Removed the whole LiveRange.
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} else
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I->start = End;
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return;
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}
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// Otherwise if the span we are removing is at the end of the LiveRange,
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// adjust the other way.
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if (I->end == End) {
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I->end = Start;
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return;
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}
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// Otherwise, we are splitting the LiveRange into two pieces.
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SlotIndex OldEnd = I->end;
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I->end = Start; // Trim the old interval.
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// Insert the new one.
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ranges.insert(llvm::next(I), LiveRange(End, OldEnd, ValNo));
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}
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/// removeValNo - Remove all the ranges defined by the specified value#.
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/// Also remove the value# from value# list.
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void LiveInterval::removeValNo(VNInfo *ValNo) {
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if (empty()) return;
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Ranges::iterator I = ranges.end();
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Ranges::iterator E = ranges.begin();
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do {
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--I;
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if (I->valno == ValNo)
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ranges.erase(I);
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} while (I != E);
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// Now that ValNo is dead, remove it.
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markValNoForDeletion(ValNo);
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}
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/// join - Join two live intervals (this, and other) together. This applies
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/// mappings to the value numbers in the LHS/RHS intervals as specified. If
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/// the intervals are not joinable, this aborts.
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void LiveInterval::join(LiveInterval &Other,
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const int *LHSValNoAssignments,
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const int *RHSValNoAssignments,
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SmallVector<VNInfo*, 16> &NewVNInfo,
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MachineRegisterInfo *MRI) {
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verify();
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// Determine if any of our live range values are mapped. This is uncommon, so
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// we want to avoid the interval scan if not.
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bool MustMapCurValNos = false;
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unsigned NumVals = getNumValNums();
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unsigned NumNewVals = NewVNInfo.size();
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for (unsigned i = 0; i != NumVals; ++i) {
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unsigned LHSValID = LHSValNoAssignments[i];
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if (i != LHSValID ||
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(NewVNInfo[LHSValID] && NewVNInfo[LHSValID] != getValNumInfo(i))) {
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MustMapCurValNos = true;
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break;
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}
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}
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// If we have to apply a mapping to our base interval assignment, rewrite it
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// now.
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if (MustMapCurValNos) {
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// Map the first live range.
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iterator OutIt = begin();
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OutIt->valno = NewVNInfo[LHSValNoAssignments[OutIt->valno->id]];
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for (iterator I = next(OutIt), E = end(); I != E; ++I) {
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VNInfo* nextValNo = NewVNInfo[LHSValNoAssignments[I->valno->id]];
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assert(nextValNo != 0 && "Huh?");
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// If this live range has the same value # as its immediate predecessor,
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// and if they are neighbors, remove one LiveRange. This happens when we
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// have [0,4:0)[4,7:1) and map 0/1 onto the same value #.
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if (OutIt->valno == nextValNo && OutIt->end == I->start) {
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OutIt->end = I->end;
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} else {
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// Didn't merge. Move OutIt to the next interval,
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++OutIt;
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OutIt->valno = nextValNo;
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if (OutIt != I) {
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OutIt->start = I->start;
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OutIt->end = I->end;
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}
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}
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}
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// If we merge some live ranges, chop off the end.
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++OutIt;
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ranges.erase(OutIt, end());
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}
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// Remember assignements because val# ids are changing.
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SmallVector<unsigned, 16> OtherAssignments;
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for (iterator I = Other.begin(), E = Other.end(); I != E; ++I)
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OtherAssignments.push_back(RHSValNoAssignments[I->valno->id]);
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// Update val# info. Renumber them and make sure they all belong to this
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// LiveInterval now. Also remove dead val#'s.
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unsigned NumValNos = 0;
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for (unsigned i = 0; i < NumNewVals; ++i) {
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VNInfo *VNI = NewVNInfo[i];
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if (VNI) {
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if (NumValNos >= NumVals)
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valnos.push_back(VNI);
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else
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valnos[NumValNos] = VNI;
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VNI->id = NumValNos++; // Renumber val#.
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}
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}
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if (NumNewVals < NumVals)
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valnos.resize(NumNewVals); // shrinkify
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// Okay, now insert the RHS live ranges into the LHS.
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unsigned RangeNo = 0;
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for (iterator I = Other.begin(), E = Other.end(); I != E; ++I, ++RangeNo) {
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// Map the valno in the other live range to the current live range.
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I->valno = NewVNInfo[OtherAssignments[RangeNo]];
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assert(I->valno && "Adding a dead range?");
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}
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mergeIntervalRanges(Other);
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verify();
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}
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/// \brief Helper function for merging in another LiveInterval's ranges.
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///
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/// This is a helper routine implementing an efficient merge of another
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/// LiveIntervals ranges into the current interval.
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///
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/// \param LHSValNo If non-NULL, set as the new value number for every range
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/// from RHS which is merged into the LHS.
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/// \param RHSValNo If non-NULL, then only ranges in RHS whose original value
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/// number maches this value number will be merged into LHS.
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void LiveInterval::mergeIntervalRanges(const LiveInterval &RHS,
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VNInfo *LHSValNo,
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const VNInfo *RHSValNo) {
|
|
if (RHS.empty())
|
|
return;
|
|
|
|
// Ensure we're starting with a valid range. Note that we don't verify RHS
|
|
// because it may have had its value numbers adjusted in preparation for
|
|
// merging.
|
|
verify();
|
|
|
|
// The strategy for merging these efficiently is as follows:
|
|
//
|
|
// 1) Find the beginning of the impacted ranges in the LHS.
|
|
// 2) Create a new, merged sub-squence of ranges merging from the position in
|
|
// #1 until either LHS or RHS is exhausted. Any part of LHS between RHS
|
|
// entries being merged will be copied into this new range.
|
|
// 3) Replace the relevant section in LHS with these newly merged ranges.
|
|
// 4) Append any remaning ranges from RHS if LHS is exhausted in #2.
|
|
//
|
|
// We don't follow the typical in-place merge strategy for sorted ranges of
|
|
// appending the new ranges to the back and then using std::inplace_merge
|
|
// because one step of the merge can both mutate the original elements and
|
|
// remove elements from the original. Essentially, because the merge includes
|
|
// collapsing overlapping ranges, a more complex approach is required.
|
|
|
|
// We do an initial binary search to optimize for a common pattern: a large
|
|
// LHS, and a very small RHS.
|
|
const_iterator RI = RHS.begin(), RE = RHS.end();
|
|
iterator LE = end(), LI = std::upper_bound(begin(), LE, *RI);
|
|
|
|
// Merge into NewRanges until one of the ranges is exhausted.
|
|
SmallVector<LiveRange, 4> NewRanges;
|
|
|
|
// Keep track of where to begin the replacement.
|
|
iterator ReplaceI = LI;
|
|
|
|
// If there are preceding ranges in the LHS, put the last one into NewRanges
|
|
// so we can optionally extend it. Adjust the replacement point accordingly.
|
|
if (LI != begin()) {
|
|
ReplaceI = llvm::prior(LI);
|
|
NewRanges.push_back(*ReplaceI);
|
|
}
|
|
|
|
// Now loop over the mergable portions of both LHS and RHS, merging into
|
|
// NewRanges.
|
|
while (LI != LE && RI != RE) {
|
|
// Skip incoming ranges with the wrong value.
|
|
if (RHSValNo && RI->valno != RHSValNo) {
|
|
++RI;
|
|
continue;
|
|
}
|
|
|
|
// Select the first range. We pick the earliest start point, and then the
|
|
// largest range.
|
|
LiveRange R = *LI;
|
|
if (*RI < R) {
|
|
R = *RI;
|
|
++RI;
|
|
if (LHSValNo)
|
|
R.valno = LHSValNo;
|
|
} else {
|
|
++LI;
|
|
}
|
|
|
|
if (NewRanges.empty()) {
|
|
NewRanges.push_back(R);
|
|
continue;
|
|
}
|
|
|
|
LiveRange &LastR = NewRanges.back();
|
|
if (R.valno == LastR.valno) {
|
|
// Try to merge this range into the last one.
|
|
if (R.start <= LastR.end) {
|
|
LastR.end = std::max(LastR.end, R.end);
|
|
continue;
|
|
}
|
|
} else {
|
|
// We can't merge ranges across a value number.
|
|
assert(R.start >= LastR.end &&
|
|
"Cannot overlap two LiveRanges with differing ValID's");
|
|
}
|
|
|
|
// If all else fails, just append the range.
|
|
NewRanges.push_back(R);
|
|
}
|
|
assert(RI == RE || LI == LE);
|
|
|
|
// Check for being able to merge into the trailing sequence of ranges on the LHS.
|
|
if (!NewRanges.empty())
|
|
for (; LI != LE && (LI->valno == NewRanges.back().valno &&
|
|
LI->start <= NewRanges.back().end);
|
|
++LI)
|
|
NewRanges.back().end = std::max(NewRanges.back().end, LI->end);
|
|
|
|
// Replace the ranges in the LHS with the newly merged ones. It would be
|
|
// really nice if there were a move-supporting 'replace' directly in
|
|
// SmallVector, but as there is not, we pay the price of copies to avoid
|
|
// wasted memory allocations.
|
|
SmallVectorImpl<LiveRange>::iterator NRI = NewRanges.begin(),
|
|
NRE = NewRanges.end();
|
|
for (; ReplaceI != LI && NRI != NRE; ++ReplaceI, ++NRI)
|
|
*ReplaceI = *NRI;
|
|
if (NRI == NRE)
|
|
ranges.erase(ReplaceI, LI);
|
|
else
|
|
ranges.insert(LI, NRI, NRE);
|
|
|
|
// And finally insert any trailing end of RHS (if we have one).
|
|
for (; RI != RE; ++RI) {
|
|
LiveRange R = *RI;
|
|
if (LHSValNo)
|
|
R.valno = LHSValNo;
|
|
if (!ranges.empty() &&
|
|
ranges.back().valno == R.valno && R.start <= ranges.back().end)
|
|
ranges.back().end = std::max(ranges.back().end, R.end);
|
|
else
|
|
ranges.push_back(R);
|
|
}
|
|
|
|
// Ensure we finished with a valid new sequence of ranges.
|
|
verify();
|
|
}
|
|
|
|
/// MergeRangesInAsValue - Merge all of the intervals in RHS into this live
|
|
/// interval as the specified value number. The LiveRanges in RHS are
|
|
/// allowed to overlap with LiveRanges in the current interval, but only if
|
|
/// the overlapping LiveRanges have the specified value number.
|
|
void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS,
|
|
VNInfo *LHSValNo) {
|
|
mergeIntervalRanges(RHS, LHSValNo);
|
|
}
|
|
|
|
/// MergeValueInAsValue - Merge all of the live ranges of a specific val#
|
|
/// in RHS into this live interval as the specified value number.
|
|
/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
|
|
/// current interval, it will replace the value numbers of the overlaped
|
|
/// live ranges with the specified value number.
|
|
void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS,
|
|
const VNInfo *RHSValNo,
|
|
VNInfo *LHSValNo) {
|
|
mergeIntervalRanges(RHS, LHSValNo, RHSValNo);
|
|
}
|
|
|
|
/// MergeValueNumberInto - This method is called when two value nubmers
|
|
/// are found to be equivalent. This eliminates V1, replacing all
|
|
/// LiveRanges with the V1 value number with the V2 value number. This can
|
|
/// cause merging of V1/V2 values numbers and compaction of the value space.
|
|
VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {
|
|
assert(V1 != V2 && "Identical value#'s are always equivalent!");
|
|
|
|
// This code actually merges the (numerically) larger value number into the
|
|
// smaller value number, which is likely to allow us to compactify the value
|
|
// space. The only thing we have to be careful of is to preserve the
|
|
// instruction that defines the result value.
|
|
|
|
// Make sure V2 is smaller than V1.
|
|
if (V1->id < V2->id) {
|
|
V1->copyFrom(*V2);
|
|
std::swap(V1, V2);
|
|
}
|
|
|
|
// Merge V1 live ranges into V2.
|
|
for (iterator I = begin(); I != end(); ) {
|
|
iterator LR = I++;
|
|
if (LR->valno != V1) continue; // Not a V1 LiveRange.
|
|
|
|
// Okay, we found a V1 live range. If it had a previous, touching, V2 live
|
|
// range, extend it.
|
|
if (LR != begin()) {
|
|
iterator Prev = LR-1;
|
|
if (Prev->valno == V2 && Prev->end == LR->start) {
|
|
Prev->end = LR->end;
|
|
|
|
// Erase this live-range.
|
|
ranges.erase(LR);
|
|
I = Prev+1;
|
|
LR = Prev;
|
|
}
|
|
}
|
|
|
|
// Okay, now we have a V1 or V2 live range that is maximally merged forward.
|
|
// Ensure that it is a V2 live-range.
|
|
LR->valno = V2;
|
|
|
|
// If we can merge it into later V2 live ranges, do so now. We ignore any
|
|
// following V1 live ranges, as they will be merged in subsequent iterations
|
|
// of the loop.
|
|
if (I != end()) {
|
|
if (I->start == LR->end && I->valno == V2) {
|
|
LR->end = I->end;
|
|
ranges.erase(I);
|
|
I = LR+1;
|
|
}
|
|
}
|
|
}
|
|
|
|
// Merge the relevant flags.
|
|
V2->mergeFlags(V1);
|
|
|
|
// Now that V1 is dead, remove it.
|
|
markValNoForDeletion(V1);
|
|
|
|
return V2;
|
|
}
|
|
|
|
void LiveInterval::Copy(const LiveInterval &RHS,
|
|
MachineRegisterInfo *MRI,
|
|
VNInfo::Allocator &VNInfoAllocator) {
|
|
ranges.clear();
|
|
valnos.clear();
|
|
std::pair<unsigned, unsigned> Hint = MRI->getRegAllocationHint(RHS.reg);
|
|
MRI->setRegAllocationHint(reg, Hint.first, Hint.second);
|
|
|
|
weight = RHS.weight;
|
|
for (unsigned i = 0, e = RHS.getNumValNums(); i != e; ++i) {
|
|
const VNInfo *VNI = RHS.getValNumInfo(i);
|
|
createValueCopy(VNI, VNInfoAllocator);
|
|
}
|
|
for (unsigned i = 0, e = RHS.ranges.size(); i != e; ++i) {
|
|
const LiveRange &LR = RHS.ranges[i];
|
|
addRange(LiveRange(LR.start, LR.end, getValNumInfo(LR.valno->id)));
|
|
}
|
|
|
|
verify();
|
|
}
|
|
|
|
unsigned LiveInterval::getSize() const {
|
|
unsigned Sum = 0;
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I)
|
|
Sum += I->start.distance(I->end);
|
|
return Sum;
|
|
}
|
|
|
|
raw_ostream& llvm::operator<<(raw_ostream& os, const LiveRange &LR) {
|
|
return os << '[' << LR.start << ',' << LR.end << ':' << LR.valno->id << ")";
|
|
}
|
|
|
|
void LiveRange::dump() const {
|
|
dbgs() << *this << "\n";
|
|
}
|
|
|
|
void LiveInterval::print(raw_ostream &OS) const {
|
|
if (empty())
|
|
OS << "EMPTY";
|
|
else {
|
|
for (LiveInterval::Ranges::const_iterator I = ranges.begin(),
|
|
E = ranges.end(); I != E; ++I) {
|
|
OS << *I;
|
|
assert(I->valno == getValNumInfo(I->valno->id) && "Bad VNInfo");
|
|
}
|
|
}
|
|
|
|
// Print value number info.
|
|
if (getNumValNums()) {
|
|
OS << " ";
|
|
unsigned vnum = 0;
|
|
for (const_vni_iterator i = vni_begin(), e = vni_end(); i != e;
|
|
++i, ++vnum) {
|
|
const VNInfo *vni = *i;
|
|
if (vnum) OS << " ";
|
|
OS << vnum << "@";
|
|
if (vni->isUnused()) {
|
|
OS << "x";
|
|
} else {
|
|
OS << vni->def;
|
|
if (vni->isPHIDef())
|
|
OS << "-phidef";
|
|
if (vni->hasPHIKill())
|
|
OS << "-phikill";
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void LiveInterval::dump() const {
|
|
dbgs() << *this << "\n";
|
|
}
|
|
|
|
#ifndef NDEBUG
|
|
void LiveInterval::verify() const {
|
|
for (const_iterator I = begin(), E = end(); I != E; ++I) {
|
|
assert(I->start.isValid());
|
|
assert(I->end.isValid());
|
|
assert(I->start < I->end);
|
|
assert(I->valno != 0);
|
|
assert(I->valno == valnos[I->valno->id]);
|
|
if (llvm::next(I) != E) {
|
|
assert(I->end <= llvm::next(I)->start);
|
|
if (I->end == llvm::next(I)->start)
|
|
assert(I->valno != llvm::next(I)->valno);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
|
|
void LiveRange::print(raw_ostream &os) const {
|
|
os << *this;
|
|
}
|
|
|
|
unsigned ConnectedVNInfoEqClasses::Classify(const LiveInterval *LI) {
|
|
// Create initial equivalence classes.
|
|
EqClass.clear();
|
|
EqClass.grow(LI->getNumValNums());
|
|
|
|
const VNInfo *used = 0, *unused = 0;
|
|
|
|
// Determine connections.
|
|
for (LiveInterval::const_vni_iterator I = LI->vni_begin(), E = LI->vni_end();
|
|
I != E; ++I) {
|
|
const VNInfo *VNI = *I;
|
|
// Group all unused values into one class.
|
|
if (VNI->isUnused()) {
|
|
if (unused)
|
|
EqClass.join(unused->id, VNI->id);
|
|
unused = VNI;
|
|
continue;
|
|
}
|
|
used = VNI;
|
|
if (VNI->isPHIDef()) {
|
|
const MachineBasicBlock *MBB = LIS.getMBBFromIndex(VNI->def);
|
|
assert(MBB && "Phi-def has no defining MBB");
|
|
// Connect to values live out of predecessors.
|
|
for (MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(),
|
|
PE = MBB->pred_end(); PI != PE; ++PI)
|
|
if (const VNInfo *PVNI = LI->getVNInfoBefore(LIS.getMBBEndIdx(*PI)))
|
|
EqClass.join(VNI->id, PVNI->id);
|
|
} else {
|
|
// Normal value defined by an instruction. Check for two-addr redef.
|
|
// FIXME: This could be coincidental. Should we really check for a tied
|
|
// operand constraint?
|
|
// Note that VNI->def may be a use slot for an early clobber def.
|
|
if (const VNInfo *UVNI = LI->getVNInfoBefore(VNI->def))
|
|
EqClass.join(VNI->id, UVNI->id);
|
|
}
|
|
}
|
|
|
|
// Lump all the unused values in with the last used value.
|
|
if (used && unused)
|
|
EqClass.join(used->id, unused->id);
|
|
|
|
EqClass.compress();
|
|
return EqClass.getNumClasses();
|
|
}
|
|
|
|
void ConnectedVNInfoEqClasses::Distribute(LiveInterval *LIV[],
|
|
MachineRegisterInfo &MRI) {
|
|
assert(LIV[0] && "LIV[0] must be set");
|
|
LiveInterval &LI = *LIV[0];
|
|
|
|
// Rewrite instructions.
|
|
for (MachineRegisterInfo::reg_iterator RI = MRI.reg_begin(LI.reg),
|
|
RE = MRI.reg_end(); RI != RE;) {
|
|
MachineOperand &MO = RI.getOperand();
|
|
MachineInstr *MI = MO.getParent();
|
|
++RI;
|
|
// DBG_VALUE instructions should have been eliminated earlier.
|
|
LiveRangeQuery LRQ(LI, LIS.getInstructionIndex(MI));
|
|
const VNInfo *VNI = MO.readsReg() ? LRQ.valueIn() : LRQ.valueDefined();
|
|
// In the case of an <undef> use that isn't tied to any def, VNI will be
|
|
// NULL. If the use is tied to a def, VNI will be the defined value.
|
|
if (!VNI)
|
|
continue;
|
|
MO.setReg(LIV[getEqClass(VNI)]->reg);
|
|
}
|
|
|
|
// Move runs to new intervals.
|
|
LiveInterval::iterator J = LI.begin(), E = LI.end();
|
|
while (J != E && EqClass[J->valno->id] == 0)
|
|
++J;
|
|
for (LiveInterval::iterator I = J; I != E; ++I) {
|
|
if (unsigned eq = EqClass[I->valno->id]) {
|
|
assert((LIV[eq]->empty() || LIV[eq]->expiredAt(I->start)) &&
|
|
"New intervals should be empty");
|
|
LIV[eq]->ranges.push_back(*I);
|
|
} else
|
|
*J++ = *I;
|
|
}
|
|
LI.ranges.erase(J, E);
|
|
|
|
// Transfer VNInfos to their new owners and renumber them.
|
|
unsigned j = 0, e = LI.getNumValNums();
|
|
while (j != e && EqClass[j] == 0)
|
|
++j;
|
|
for (unsigned i = j; i != e; ++i) {
|
|
VNInfo *VNI = LI.getValNumInfo(i);
|
|
if (unsigned eq = EqClass[i]) {
|
|
VNI->id = LIV[eq]->getNumValNums();
|
|
LIV[eq]->valnos.push_back(VNI);
|
|
} else {
|
|
VNI->id = j;
|
|
LI.valnos[j++] = VNI;
|
|
}
|
|
}
|
|
LI.valnos.resize(j);
|
|
}
|