Compile time improvements to VirtRegRewriter.

This change to VirtRegRewriter::addMBBLiveIns adds live-in registers for each
MachineBasicBlock's LiveIns set without isLiveIn checks as they are being added
because doing so is expensive. After all live-in registers are added, the LiveIn
vectors are sorted and uniqued.

llvm-svn: 238008

1 files changed, 7 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/VirtRegMap.cpp b/llvm/lib/CodeGen/VirtRegMap.cpp
index d9adfdf7b2e..9fb1b5b65fb 100644
--- a/llvm/lib/CodeGen/VirtRegMap.cpp
+++ b/llvm/lib/CodeGen/VirtRegMap.cpp
@@ -264,8 +264,7 @@ void VirtRegRewriter::addMBBLiveIns() {
             if ((SubRegLaneMask & S.LaneMask) == 0)
               continue;
             for (unsigned i = 0, e = LiveIn.size(); i != e; ++i) {
-              if (!LiveIn[i]->isLiveIn(SubReg))
-                LiveIn[i]->addLiveIn(SubReg);
+              LiveIn[i]->addLiveIn(SubReg);
             }
           }
           LiveIn.clear();
@@ -277,12 +276,16 @@ void VirtRegRewriter::addMBBLiveIns() {
         if (!Indexes->findLiveInMBBs(Seg.start, Seg.end, LiveIn))
           continue;
         for (unsigned i = 0, e = LiveIn.size(); i != e; ++i)
-          if (!LiveIn[i]->isLiveIn(PhysReg))
-            LiveIn[i]->addLiveIn(PhysReg);
+          LiveIn[i]->addLiveIn(PhysReg);
         LiveIn.clear();
       }
     }
   }
+
+  // Sort and unique MBB LiveIns as we've not checked if SubReg/PhysReg were in
+  // each MBB's LiveIns set before calling addLiveIn on them.
+  for (MachineBasicBlock &MBB : *MF)
+    MBB.sortUniqueLiveIns();
 }
 
 void VirtRegRewriter::rewrite() {