diff options
Diffstat (limited to 'llvm/lib/CodeGen/MachineSink.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/MachineSink.cpp | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp index 832147e..0ac176e 100644 --- a/llvm/lib/CodeGen/MachineSink.cpp +++ b/llvm/lib/CodeGen/MachineSink.cpp @@ -97,6 +97,11 @@ SinkInstsIntoLoop("sink-insts-to-avoid-spills", "register spills"), cl::init(false), cl::Hidden); +static cl::opt<unsigned> SinkIntoLoopLimit( + "machine-sink-loop-limit", + cl::desc("The maximum number of instructions considered for loop sinking."), + cl::init(50), cl::Hidden); + STATISTIC(NumSunk, "Number of machine instructions sunk"); STATISTIC(NumLoopSunk, "Number of machine instructions sunk into a loop"); STATISTIC(NumSplit, "Number of critical edges split"); @@ -468,7 +473,15 @@ bool MachineSinking::runOnMachineFunction(MachineFunction &MF) { // Walk the candidates in reverse order so that we start with the use // of a def-use chain, if there is any. + // TODO: Sort the candidates using a cost-model. + unsigned i = 0; for (auto It = Candidates.rbegin(); It != Candidates.rend(); ++It) { + if (i++ == SinkIntoLoopLimit) { + LLVM_DEBUG(dbgs() << "LoopSink: Limit reached of instructions to " + "be analysed."); + break; + } + MachineInstr *I = *It; if (!SinkIntoLoop(L, *I)) break; @@ -1243,6 +1256,10 @@ bool MachineSinking::SinkIntoLoop(MachineLoop *L, MachineInstr &I) { LLVM_DEBUG(dbgs() << "LoopSink: Not sinking, sink block is the preheader\n"); return false; } + if (SinkBlock->size() > SinkLoadInstsPerBlockThreshold) { + LLVM_DEBUG(dbgs() << "LoopSink: Not Sinking, block too large to analyse.\n"); + return false; + } LLVM_DEBUG(dbgs() << "LoopSink: Sinking instruction!\n"); SinkBlock->splice(SinkBlock->getFirstNonPHI(), Preheader, I); |