[MachineOutliner][NFC] Use MBB flags to avoid call checks in getOutliningInfo

We already determine a bunch of information about an MBB in
getMachineOutlinerMBBFlags. We can reuse that information to avoid calculating
things that must be false/true.

The first thing we can easily check is if an outlined sequence could ever
contain calls. There's no reason to walk over the outlined range, checking for
calls, if we already know that there are no calls in the block containing the
sequence.

llvm-svn: 346809

1 files changed, 9 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index 6b9fadd..49d0893a 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -625,6 +625,9 @@ struct InstructionMapper {
   /// Inverse of \p InstructionIntegerMap.
   DenseMap<unsigned, MachineInstr *> IntegerInstructionMap;
 
+  /// Correspondence between \p MachineBasicBlocks and target-defined flags.
+  DenseMap<MachineBasicBlock *, unsigned> MBBFlagsMap;
+
   /// The vector of unsigned integers that the module is mapped to.
   std::vector<unsigned> UnsignedVec;
 
@@ -748,6 +751,9 @@ struct InstructionMapper {
     if (!TII.isMBBSafeToOutlineFrom(MBB, Flags))
       return;
 
+    // Store info for the MBB for later outlining.
+    MBBFlagsMap[&MBB] = Flags;
+
     MachineBasicBlock::iterator It = MBB.begin();
 
     // The number of instructions in this block that will be considered for
@@ -1106,10 +1112,11 @@ unsigned MachineOutliner::findCandidates(
 
         MachineBasicBlock::iterator StartIt = Mapper.InstrList[StartIdx];
         MachineBasicBlock::iterator EndIt = Mapper.InstrList[EndIdx];
+        MachineBasicBlock *MBB = StartIt->getParent();
 
         CandidatesForRepeatedSeq.emplace_back(StartIdx, StringLen, StartIt,
-                                              EndIt, StartIt->getParent(),
-                                              FunctionList.size());
+                                              EndIt, MBB, FunctionList.size(),
+                                              Mapper.MBBFlagsMap[MBB]);
       }
     }