1 files changed, 18 insertions, 12 deletions

diff --git a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
index f9eec7d4006..3afadab6c17 100644
--- a/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ b/llvm/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -2161,33 +2161,39 @@ bool ARMPreAllocLoadStoreOpt::RescheduleOps(MachineBasicBlock *MBB,
     unsigned LastBytes = 0;
     unsigned NumMove = 0;
     for (int i = Ops.size() - 1; i >= 0; --i) {
+      // Make sure each operation has the same kind.
       MachineInstr *Op = Ops[i];
-      unsigned Loc = MI2LocMap[Op];
-      if (Loc <= FirstLoc) {
-        FirstLoc = Loc;
-        FirstOp = Op;
-      }
-      if (Loc >= LastLoc) {
-        LastLoc = Loc;
-        LastOp = Op;
-      }
-
       unsigned LSMOpcode
         = getLoadStoreMultipleOpcode(Op->getOpcode(), ARM_AM::ia);
       if (LastOpcode && LSMOpcode != LastOpcode)
         break;
 
+      // Check that we have a continuous set of offsets.
       int Offset = getMemoryOpOffset(*Op);
       unsigned Bytes = getLSMultipleTransferSize(Op);
       if (LastBytes) {
         if (Bytes != LastBytes || Offset != (LastOffset + (int)Bytes))
           break;
       }
+
+      // Don't try to reschedule too many instructions.
+      if (++NumMove == 8) // FIXME: Tune this limit.
+        break;
+
+      // Found a mergable instruction; save information about it.
       LastOffset = Offset;
       LastBytes = Bytes;
       LastOpcode = LSMOpcode;
-      if (++NumMove == 8) // FIXME: Tune this limit.
-        break;
+
+      unsigned Loc = MI2LocMap[Op];
+      if (Loc <= FirstLoc) {
+        FirstLoc = Loc;
+        FirstOp = Op;
+      }
+      if (Loc >= LastLoc) {
+        LastLoc = Loc;
+        LastOp = Op;
+      }
     }
 
     if (NumMove <= 1)