Don't coalesce identical DBG_VALUE instructions prematurely.

Each of these instructions may have a RegsClobberInsn entry that can't be
ignored. Consecutive ranges are coalesced later when DwarfDebug::emitDebugLoc
merges entries.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128155 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 7c50b1e..58d51ea 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -2419,14 +2419,12 @@
     if (Processed.count(DV) != 0)
       continue;
 
-    const MachineInstr *PrevMI = MInsn;
     for (SmallVector<const MachineInstr *, 8>::iterator MI = I+1,
            ME = DbgValues.end(); MI != ME; ++MI) {
       const MDNode *Var =
         (*MI)->getOperand((*MI)->getNumOperands()-1).getMetadata();
-      if (Var == DV && !PrevMI->isIdenticalTo(*MI))
+      if (Var == DV)
         MultipleValues.push_back(*MI);
-      PrevMI = *MI;
     }
 
     DbgScope *Scope = NULL;