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author | Evan Cheng <evan.cheng@apple.com> | 2008-10-27 23:21:01 +0000 |
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committer | Evan Cheng <evan.cheng@apple.com> | 2008-10-27 23:21:01 +0000 |
commit | b3990d5e948769a16d4ee77dbdff8a2bed8fb126 (patch) | |
tree | 576c709653e9a0f2655487d66bc267a007660b8d /lib | |
parent | 8e7fa916fe87733b3660466b3a1c91d650c473d3 (diff) | |
download | external_llvm-b3990d5e948769a16d4ee77dbdff8a2bed8fb126.zip external_llvm-b3990d5e948769a16d4ee77dbdff8a2bed8fb126.tar.gz external_llvm-b3990d5e948769a16d4ee77dbdff8a2bed8fb126.tar.bz2 |
Remove val# defined by a remat'ed def that is now dead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58294 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
-rw-r--r-- | lib/CodeGen/PreAllocSplitting.cpp | 3 | ||||
-rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.cpp | 27 | ||||
-rw-r--r-- | lib/CodeGen/SimpleRegisterCoalescing.h | 5 |
3 files changed, 33 insertions, 2 deletions
diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp index 33e3e80..0969440 100644 --- a/lib/CodeGen/PreAllocSplitting.cpp +++ b/lib/CodeGen/PreAllocSplitting.cpp @@ -561,6 +561,9 @@ bool PreAllocSplitting::SplitRegLiveInterval(LiveInterval *LI) { SpillMI = prior(SpillPt); LIs->InsertMachineInstrInMaps(SpillMI, SpillIndex); } else if (!PrevSpilled) { + if (!DefMI) + // Def is dead. Do nothing. + return false; // If it's already split, just restore the value. There is no need to spill // the def again. // Check if it's possible to insert a spill after the def MI. diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp index 6eeb21c..a60939c 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.cpp +++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp @@ -707,6 +707,18 @@ bool SimpleRegisterCoalescing::ShortenDeadCopyLiveRange(LiveInterval &li, return false; } +/// RemoveDeadDef - If a def of a live interval is now determined dead, remove +/// the val# it defines. If the live interval becomes empty, remove it as well. +bool SimpleRegisterCoalescing::RemoveDeadDef(LiveInterval &li, + MachineInstr *DefMI) { + unsigned DefIdx = li_->getDefIndex(li_->getInstructionIndex(DefMI)); + LiveInterval::iterator MLR = li.FindLiveRangeContaining(DefIdx); + if (DefIdx != MLR->valno->def) + return false; + li.removeValNo(MLR->valno); + return removeIntervalIfEmpty(li, li_, tri_); +} + /// PropagateDeadness - Propagate the dead marker to the instruction which /// defines the val#. static void PropagateDeadness(LiveInterval &li, MachineInstr *CopyMI, @@ -2280,6 +2292,7 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) { // Perform a final pass over the instructions and compute spill weights // and remove identity moves. + SmallVector<unsigned, 4> DeadDefs; for (MachineFunction::iterator mbbi = mf_->begin(), mbbe = mf_->end(); mbbi != mbbe; ++mbbi) { MachineBasicBlock* mbb = mbbi; @@ -2313,9 +2326,13 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) { bool isDead = true; for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) { const MachineOperand &MO = MI->getOperand(i); - if (!MO.isReg() || MO.isDead()) + if (!MO.isReg()) continue; unsigned Reg = MO.getReg(); + if (TargetRegisterInfo::isVirtualRegister(Reg)) + DeadDefs.push_back(Reg); + if (MO.isDead()) + continue; if (TargetRegisterInfo::isPhysicalRegister(Reg) || !mri_->use_empty(Reg)) { isDead = false; @@ -2323,10 +2340,16 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) { } } if (isDead) { + while (!DeadDefs.empty()) { + unsigned DeadDef = DeadDefs.back(); + DeadDefs.pop_back(); + RemoveDeadDef(li_->getInterval(DeadDef), MI); + } li_->RemoveMachineInstrFromMaps(mii); mii = mbbi->erase(mii); continue; - } + } else + DeadDefs.clear(); } // If the move will be an identity move delete it diff --git a/lib/CodeGen/SimpleRegisterCoalescing.h b/lib/CodeGen/SimpleRegisterCoalescing.h index 330c476..abe3929 100644 --- a/lib/CodeGen/SimpleRegisterCoalescing.h +++ b/lib/CodeGen/SimpleRegisterCoalescing.h @@ -269,6 +269,11 @@ namespace llvm { /// live range is dead. Return true if live interval is removed. bool ShortenDeadCopySrcLiveRange(LiveInterval &li, MachineInstr *CopyMI); + /// RemoveDeadDef - If a def of a live interval is now determined dead, + /// remove the val# it defines. If the live interval becomes empty, remove + /// it as well. + bool RemoveDeadDef(LiveInterval &li, MachineInstr *DefMI); + /// lastRegisterUse - Returns the last use of the specific register between /// cycles Start and End or NULL if there are no uses. MachineOperand *lastRegisterUse(unsigned Start, unsigned End, unsigned Reg, |