[llvm-commits] [llvm] r150220 - /llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Thu Feb  9 19:31:31 2012
New Revision: 150220

URL: http://llvm.org/viewvc/llvm-project?rev=150220&view=rev
Log:
Constrain the regmask search space for local live ranges.

When checking a local live range for interference, restrict the binary
search to the single block.

Modified:
    llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp

Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=150220&r1=150219&r2=150220&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Thu Feb  9 19:31:31 2012
@@ -1161,11 +1161,21 @@
                                              BitVector &UsableRegs) {
   if (LI.empty())
     return false;
+  LiveInterval::iterator LiveI = LI.begin(), LiveE = LI.end();
+
+  // Use a smaller arrays for local live ranges.
+  ArrayRef<SlotIndex> Slots;
+  ArrayRef<const uint32_t*> Bits;
+  if (MachineBasicBlock *MBB = intervalIsInOneMBB(LI)) {
+    Slots = getRegMaskSlotsInBlock(MBB->getNumber());
+    Bits = getRegMaskBitsInBlock(MBB->getNumber());
+  } else {
+    Slots = getRegMaskSlots();
+    Bits = getRegMaskBits();
+  }
 
   // We are going to enumerate all the register mask slots contained in LI.
   // Start with a binary search of RegMaskSlots to find a starting point.
-  LiveInterval::iterator LiveI = LI.begin(), LiveE = LI.end();
-  ArrayRef<SlotIndex> Slots = getRegMaskSlots();
   ArrayRef<SlotIndex>::iterator SlotI =
     std::lower_bound(Slots.begin(), Slots.end(), LiveI->start);
   ArrayRef<SlotIndex>::iterator SlotE = Slots.end();
@@ -1187,7 +1197,7 @@
         Found = true;
       }
       // Remove usable registers clobbered by this mask.
-      UsableRegs.clearBitsNotInMask(RegMaskBits[SlotI-Slots.begin()]);
+      UsableRegs.clearBitsNotInMask(Bits[SlotI-Slots.begin()]);
       if (++SlotI == SlotE)
         return Found;
     }