6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-02-04 07:32:13 +00:00
Code Issues Projects Releases Wiki Activity

Don't shrink live ranges after dead code elimination unless it is going to help.

Browse Source 
In particular, don't repeatedly recompute the PIC base live range after rematerialization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129275 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-04-11 15:00:39 +00:00
parent ff688a1f6e
commit 1edc3cf65d
1 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
lib/CodeGen/LiveRangeEdit.cpp
View File

@ -203,6 +203,7 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
SetVector<LiveInterval*,
SmallVector<LiveInterval*, 8>,
SmallPtrSet<LiveInterval*, 8> > ToShrink;
MachineRegisterInfo &MRI = VRM.getRegInfo();
for (;;) {
// Erase all dead defs.
@ -236,8 +237,13 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
continue;
LiveInterval &LI = LIS.getInterval(Reg);
// Shrink read registers.
if (MI->readsVirtualRegister(Reg))
// Shrink read registers, unless it is likely to be expensive and
// unlikely to change anything. We typically don't want to shrink the
// PIC base register that has lots of uses everywhere.
// Always shrink COPY uses that probably come from live range splitting.
if (MI->readsVirtualRegister(Reg) &&
(MI->isCopy() || MOI->isDef() || MRI.hasOneNonDBGUse(Reg) ||
LI.killedAt(Idx)))
ToShrink.insert(&LI);
// Remove defined value.
@ -266,7 +272,7 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
// Shrink just one live interval. Then delete new dead defs.
LiveInterval *LI = ToShrink.back();
ToShrink.pop_back();
if (foldAsLoad(LI, Dead, VRM.getRegInfo(), LIS, TII))
if (foldAsLoad(LI, Dead, MRI, LIS, TII))
continue;
if (delegate_)
delegate_->LRE_WillShrinkVirtReg(LI->reg);
@ -286,7 +292,7 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
if (delegate_)
delegate_->LRE_DidCloneVirtReg(Dups.back()->reg, LI->reg);
}
ConEQ.Distribute(&Dups[0], VRM.getRegInfo());
ConEQ.Distribute(&Dups[0], MRI);
}
}