diff options
| -rw-r--r-- | include/llvm/CodeGen/LiveIntervalAnalysis.h | 2 | ||||
| -rw-r--r-- | lib/CodeGen/LiveIntervalAnalysis.cpp | 46 | ||||
| -rw-r--r-- | lib/CodeGen/VirtRegMap.cpp | 2 |
3 files changed, 46 insertions, 4 deletions
diff --git a/include/llvm/CodeGen/LiveIntervalAnalysis.h b/include/llvm/CodeGen/LiveIntervalAnalysis.h index da521dbc53..bf7469093a 100644 --- a/include/llvm/CodeGen/LiveIntervalAnalysis.h +++ b/include/llvm/CodeGen/LiveIntervalAnalysis.h @@ -252,7 +252,7 @@ namespace llvm { /// addKillFlags - Add kill flags to any instruction that kills a virtual /// register. - void addKillFlags(); + void addKillFlags(const VirtRegMap*); /// handleMove - call this method to notify LiveIntervals that /// instruction 'mi' has been moved within a basic block. This will update diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index bdf4f2dfff..b447c3c2d7 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -34,6 +34,7 @@ #include "llvm/ADT/DenseSet.h" #include "llvm/ADT/STLExtras.h" #include "LiveRangeCalc.h" +#include "VirtRegMap.h" #include <algorithm> #include <limits> #include <cmath> @@ -733,12 +734,28 @@ bool LiveIntervals::shrinkToUses(LiveInterval *li, // Register allocator hooks. // -void LiveIntervals::addKillFlags() { +void LiveIntervals::addKillFlags(const VirtRegMap *VRM) { + // Keep track of regunit ranges. + SmallVector<std::pair<LiveInterval*, LiveInterval::iterator>, 8> RU; + for (unsigned i = 0, e = MRI->getNumVirtRegs(); i != e; ++i) { unsigned Reg = TargetRegisterInfo::index2VirtReg(i); if (MRI->reg_nodbg_empty(Reg)) continue; LiveInterval *LI = &getInterval(Reg); + if (LI->empty()) + continue; + + // Find the regunit intervals for the assigned register. They may overlap + // the virtual register live range, cancelling any kills. + RU.clear(); + for (MCRegUnitIterator Units(VRM->getPhys(Reg), TRI); Units.isValid(); + ++Units) { + LiveInterval *RUInt = &getRegUnit(*Units); + if (RUInt->empty()) + continue; + RU.push_back(std::make_pair(RUInt, RUInt->find(LI->begin()->end))); + } // Every instruction that kills Reg corresponds to a live range end point. for (LiveInterval::iterator RI = LI->begin(), RE = LI->end(); RI != RE; @@ -749,7 +766,32 @@ void LiveIntervals::addKillFlags() { MachineInstr *MI = getInstructionFromIndex(RI->end); if (!MI) continue; - MI->addRegisterKilled(Reg, NULL); + + // Check if any of the reguints are live beyond the end of RI. That could + // happen when a physreg is defined as a copy of a virtreg: + // + // %EAX = COPY %vreg5 + // FOO %vreg5 <--- MI, cancel kill because %EAX is live. + // BAR %EAX<kill> + // + // There should be no kill flag on FOO when %vreg5 is rewritten as %EAX. + bool CancelKill = false; + for (unsigned u = 0, e = RU.size(); u != e; ++u) { + LiveInterval *RInt = RU[u].first; + LiveInterval::iterator &I = RU[u].second; + if (I == RInt->end()) + continue; + I = RInt->advanceTo(I, RI->end); + if (I == RInt->end() || I->start >= RI->end) + continue; + // I is overlapping RI. + CancelKill = true; + break; + } + if (CancelKill) + MI->clearRegisterKills(Reg, NULL); + else + MI->addRegisterKilled(Reg, NULL); } } } diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp index a1cac7c5b2..6343e8a352 100644 --- a/lib/CodeGen/VirtRegMap.cpp +++ b/lib/CodeGen/VirtRegMap.cpp @@ -200,7 +200,7 @@ bool VirtRegRewriter::runOnMachineFunction(MachineFunction &fn) { DEBUG(VRM->dump()); // Add kill flags while we still have virtual registers. - LIS->addKillFlags(); + LIS->addKillFlags(VRM); // Live-in lists on basic blocks are required for physregs. addMBBLiveIns(); |