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| author | rdivacky <rdivacky@FreeBSD.org> | 2010-05-04 16:11:02 +0000 |
|---|---|---|
| committer | rdivacky <rdivacky@FreeBSD.org> | 2010-05-04 16:11:02 +0000 |
| commit | 750ce4d809c7e2a298a389a512a17652ff5be3f2 (patch) | |
| tree | 70fbd90da02177c8e6ef82adba9fa8ace285a5e3 /lib/CodeGen/MachineSink.cpp | |
| parent | 5f970ec96e421f64db6b1c6509a902ea73d98cc7 (diff) | |
| download | FreeBSD-src-750ce4d809c7e2a298a389a512a17652ff5be3f2.zip FreeBSD-src-750ce4d809c7e2a298a389a512a17652ff5be3f2.tar.gz | |
Update LLVM to r103004.
Diffstat (limited to 'lib/CodeGen/MachineSink.cpp')
| -rw-r--r-- | lib/CodeGen/MachineSink.cpp | 30 |
1 files changed, 28 insertions, 2 deletions
diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp index e659619..ef489dc 100644 --- a/lib/CodeGen/MachineSink.cpp +++ b/lib/CodeGen/MachineSink.cpp @@ -20,6 +20,7 @@ #include "llvm/CodeGen/Passes.h" #include "llvm/CodeGen/MachineRegisterInfo.h" #include "llvm/CodeGen/MachineDominators.h" +#include "llvm/CodeGen/MachineLoopInfo.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Target/TargetRegisterInfo.h" #include "llvm/Target/TargetInstrInfo.h" @@ -37,6 +38,7 @@ namespace { const TargetRegisterInfo *TRI; MachineRegisterInfo *RegInfo; // Machine register information MachineDominatorTree *DT; // Machine dominator tree + MachineLoopInfo *LI; AliasAnalysis *AA; BitVector AllocatableSet; // Which physregs are allocatable? @@ -51,7 +53,9 @@ namespace { MachineFunctionPass::getAnalysisUsage(AU); AU.addRequired<AliasAnalysis>(); AU.addRequired<MachineDominatorTree>(); + AU.addRequired<MachineLoopInfo>(); AU.addPreserved<MachineDominatorTree>(); + AU.addPreserved<MachineLoopInfo>(); } private: bool ProcessBlock(MachineBasicBlock &MBB); @@ -102,6 +106,7 @@ bool MachineSinking::runOnMachineFunction(MachineFunction &MF) { TRI = TM.getRegisterInfo(); RegInfo = &MF.getRegInfo(); DT = &getAnalysis<MachineDominatorTree>(); + LI = &getAnalysis<MachineLoopInfo>(); AA = &getAnalysis<AliasAnalysis>(); AllocatableSet = TRI->getAllocatableSet(MF); @@ -276,8 +281,29 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) { // but for now we just punt. // FIXME: Split critical edges if not backedges. if (SuccToSinkTo->pred_size() > 1) { - DEBUG(dbgs() << " *** PUNTING: Critical edge found\n"); - return false; + // We cannot sink a load across a critical edge - there may be stores in + // other code paths. + bool store = true; + if (!MI->isSafeToMove(TII, AA, store)) { + DEBUG(dbgs() << " *** PUNTING: Wont sink load along critical edge.\n"); + return false; + } + + // We don't want to sink across a critical edge if we don't dominate the + // successor. We could be introducing calculations to new code paths. + if (!DT->dominates(ParentBlock, SuccToSinkTo)) { + DEBUG(dbgs() << " *** PUNTING: Critical edge found\n"); + return false; + } + + // Don't sink instructions into a loop. + if (LI->isLoopHeader(SuccToSinkTo)) { + DEBUG(dbgs() << " *** PUNTING: Loop header found\n"); + return false; + } + + // Otherwise we are OK with sinking along a critical edge. + DEBUG(dbgs() << "Sinking along critical edge.\n"); } // Determine where to insert into. Skip phi nodes. |
