Changes in directory llvm/lib/CodeGen:
LiveIntervalAnalysis.cpp updated: 1.222 -> 1.223
---
Log message:
- Merge UsedBlocks info after two virtual registers are coalesced.
- Use distance to closest use to determine whether to abort coalescing.
---
Diffs of the changes: (+30 -23)
LiveIntervalAnalysis.cpp | 53 ++++++++++++++++++++++++++---------------------
1 files changed, 30 insertions(+), 23 deletions(-)
Index: llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
diff -u llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.222
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.223
--- llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.222 Sat Mar 17 04:27:35 2007
+++ llvm/lib/CodeGen/LiveIntervalAnalysis.cpp Sun Mar 18 04:05:55 2007
@@ -940,48 +940,50 @@
if (ReduceJoinPhys && !isDead &&
MRegisterInfo::isPhysicalRegister(repSrcReg)) {
// Small function. No need to worry!
- if (r2iMap_.size() <= allocatableRegs_.size() * 2)
+ unsigned Threshold = allocatableRegs_.count() * 2;
+ if (r2iMap_.size() <= Threshold)
goto TryJoin;
LiveVariables::VarInfo& dvi = lv_->getVarInfo(repDstReg);
// Is the value used in the current BB or any immediate successroe BB?
- MachineBasicBlock *SrcBB = CopyMI->getParent();
- if (!dvi.UsedBlocks[SrcBB->getNumber()]) {
- for (MachineBasicBlock::succ_iterator SI = SrcBB->succ_begin(),
- SE = SrcBB->succ_end(); SI != SE; ++SI) {
- MachineBasicBlock *SuccMBB = *SI;
- if (dvi.UsedBlocks[SuccMBB->getNumber()])
+ MachineBasicBlock *CopyBB = CopyMI->getParent();
+ if (dvi.UsedBlocks[CopyBB->getNumber()])
+ goto TryJoin;
+ for (MachineBasicBlock::succ_iterator SI = CopyBB->succ_begin(),
+ SE = CopyBB->succ_end(); SI != SE; ++SI) {
+ MachineBasicBlock *SuccMBB = *SI;
+ if (dvi.UsedBlocks[SuccMBB->getNumber()])
goto TryJoin;
- }
}
// Ok, no use in this BB and no use in immediate successor BB's. Be really
// careful now!
// It's only used in one BB, forget about it!
- if (dvi.UsedBlocks.count() <= 1) {
+ if (dvi.UsedBlocks.count() < 2) {
++numAborts;
return false;
}
- // Examine all the blocks where the value is used. If any is in the same
- // loop, then it's ok. Or if the current BB is a preheader of any of the
- // loop that uses this value, that's ok as well.
- const LoopInfo &LI = getAnalysis<LoopInfo>();
- const Loop *L = LI.getLoopFor(SrcBB->getBasicBlock());
+ // Determine whether to allow coalescing based on how far the closest
+ // use is.
+ unsigned CopyIdx = getInstructionIndex(CopyMI);
+ unsigned MinDist = i2miMap_.size() * InstrSlots::NUM;
int UseBBNum = dvi.UsedBlocks.find_first();
while (UseBBNum != -1) {
MachineBasicBlock *UseBB = mf_->getBlockNumbered(UseBBNum);
- const Loop *UL = LI.getLoopFor(UseBB->getBasicBlock());
- if ((UL && UL == L) || // A use in the same loop
- (UL && L && // A use in a loop and this BB is the preheader
- UL->getLoopPreheader() == SrcBB->getBasicBlock()))
- goto TryJoin;
+ unsigned UseIdx = getMBBStartIdx(UseBB);
+ if (UseIdx > CopyIdx) {
+ MinDist = std::min(MinDist, UseIdx - CopyIdx);
+ if (MinDist <= Threshold)
+ break;
+ }
UseBBNum = dvi.UsedBlocks.find_next(UseBBNum);
}
-
- // Don't do it!
- ++numAborts;
- return false;
+ if (MinDist > Threshold) {
+ // Don't do it!
+ ++numAborts;
+ return false;
+ }
}
TryJoin:
@@ -1038,6 +1040,11 @@
if (MRegisterInfo::isPhysicalRegister(repDstReg)) {
for (const unsigned *AS = mri_->getAliasSet(repDstReg); *AS; ++AS)
getInterval(*AS).MergeInClobberRanges(SrcInt);
+ } else {
+ // Merge UsedBlocks info if the destination is a virtual register.
+ LiveVariables::VarInfo& dVI = lv_->getVarInfo(repDstReg);
+ LiveVariables::VarInfo& sVI = lv_->getVarInfo(repSrcReg);
+ dVI.UsedBlocks |= sVI.UsedBlocks;
}
DOUT << "\n\t\tJoined. Result = "; DestInt.print(DOUT, mri_);
_______________________________________________
llvm-commits mailing list
llvm-commits@cs.uiuc.edu
http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
