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Teach AdjustCopiesBackFrom to also use CoalescerPair to identify compatible copies.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106780 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2010-06-24 20:16:00 +00:00
parent e5ff9ef195
commit c0490ac915
2 changed files with 13 additions and 16 deletions
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26
lib/CodeGen/SimpleRegisterCoalescing.cpp
View File

@ -99,9 +99,12 @@ void SimpleRegisterCoalescing::getAnalysisUsage(AnalysisUsage &AU) const {
///
/// This returns true if an interval was modified.
///
bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
LiveInterval &IntB,
bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(const CoalescerPair &CP,
MachineInstr *CopyMI) {
LiveInterval &IntA =
li_->getInterval(CP.isFlipped() ? CP.getDstReg() : CP.getSrcReg());
LiveInterval &IntB =
li_->getInterval(CP.isFlipped() ? CP.getSrcReg() : CP.getDstReg());
SlotIndex CopyIdx = li_->getInstructionIndex(CopyMI).getDefIndex();
// BValNo is a value number in B that is defined by a copy from A. 'B3' in
@ -145,26 +148,21 @@ bool SimpleRegisterCoalescing::AdjustCopiesBackFrom(LiveInterval &IntA,
// If AValNo is defined as a copy from IntB, we can potentially process this.
// Get the instruction that defines this value number.
unsigned SrcReg = li_->getVNInfoSourceReg(AValNo);
if (!SrcReg) return false; // Not defined by a copy.
// If the value number is not defined by a copy instruction, ignore it.
// If the source register comes from an interval other than IntB, we can't
// handle this.
if (SrcReg != IntB.reg) return false;
if (!CP.isCoalescable(AValNo->getCopy()))
return false;
// Get the LiveRange in IntB that this value number starts with.
LiveInterval::iterator ValLR =
IntB.FindLiveRangeContaining(AValNo->def.getPrevSlot());
assert(ValLR != IntB.end() && "Live range not found!");
if (ValLR == IntB.end())
return false;
// Make sure that the end of the live range is inside the same block as
// CopyMI.
MachineInstr *ValLREndInst =
li_->getInstructionFromIndex(ValLR->end.getPrevSlot());
if (!ValLREndInst ||
ValLREndInst->getParent() != CopyMI->getParent()) return false;
if (!ValLREndInst || ValLREndInst->getParent() != CopyMI->getParent())
return false;
// Okay, we now know that ValLR ends in the same block that the CopyMI
// live-range starts. If there are no intervening live ranges between them in
@ -1183,7 +1181,7 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
LiveInterval *DefInt = &li_->getInterval(CP.getDstReg());
if (CP.isFlipped())
std::swap(UseInt, DefInt);
if (AdjustCopiesBackFrom(*UseInt, *DefInt, CopyMI) ||
if (AdjustCopiesBackFrom(CP, CopyMI) ||
RemoveCopyByCommutingDef(*UseInt, *DefInt, CopyMI)) {
JoinedCopies.insert(CopyMI);
DEBUG(dbgs() << "\tTrivial!\n");

3
lib/CodeGen/SimpleRegisterCoalescing.h
View File

@ -119,8 +119,7 @@ namespace llvm {
/// the source value number is defined by a copy from the destination reg
/// see if we can merge these two destination reg valno# into a single
/// value number, eliminating a copy.
bool AdjustCopiesBackFrom(LiveInterval &IntA, LiveInterval &IntB,
MachineInstr *CopyMI);
bool AdjustCopiesBackFrom(const CoalescerPair &CP, MachineInstr *CopyMI);
/// HasOtherReachingDefs - Return true if there are definitions of IntB
/// other than BValNo val# that can reach uses of AValno val# of IntA.