Rename DEBUG macro to LLVM_DEBUG.
    
The DEBUG() macro is very generic so it might clash with other projects.
The renaming was done as follows:
- git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g'
- git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM
- Manual change to APInt
- Manually chage DOCS as regex doesn't match it.

In the transition period the DEBUG() macro is still present and aliased
to the LLVM_DEBUG() one.

Differential Revision: https://reviews.llvm.org/D43624

llvm-svn: 332240
diff --git a/llvm/lib/CodeGen/MachineCSE.cpp b/llvm/lib/CodeGen/MachineCSE.cpp
index 75a3d07..cca4aa8 100644
--- a/llvm/lib/CodeGen/MachineCSE.cpp
+++ b/llvm/lib/CodeGen/MachineCSE.cpp
@@ -178,8 +178,8 @@
       continue;
     if (!MRI->constrainRegAttrs(SrcReg, Reg))
       continue;
-    DEBUG(dbgs() << "Coalescing: " << *DefMI);
-    DEBUG(dbgs() << "***     to: " << *MI);
+    LLVM_DEBUG(dbgs() << "Coalescing: " << *DefMI);
+    LLVM_DEBUG(dbgs() << "***     to: " << *MI);
     // Propagate SrcReg of copies to MI.
     MO.setReg(SrcReg);
     MRI->clearKillFlags(SrcReg);
@@ -455,13 +455,13 @@
 }
 
 void MachineCSE::EnterScope(MachineBasicBlock *MBB) {
-  DEBUG(dbgs() << "Entering: " << MBB->getName() << '\n');
+  LLVM_DEBUG(dbgs() << "Entering: " << MBB->getName() << '\n');
   ScopeType *Scope = new ScopeType(VNT);
   ScopeMap[MBB] = Scope;
 }
 
 void MachineCSE::ExitScope(MachineBasicBlock *MBB) {
-  DEBUG(dbgs() << "Exiting: " << MBB->getName() << '\n');
+  LLVM_DEBUG(dbgs() << "Exiting: " << MBB->getName() << '\n');
   DenseMap<MachineBasicBlock*, ScopeType*>::iterator SI = ScopeMap.find(MBB);
   assert(SI != ScopeMap.end());
   delete SI->second;
@@ -545,8 +545,8 @@
     // Found a common subexpression, eliminate it.
     unsigned CSVN = VNT.lookup(MI);
     MachineInstr *CSMI = Exps[CSVN];
-    DEBUG(dbgs() << "Examining: " << *MI);
-    DEBUG(dbgs() << "*** Found a common subexpression: " << *CSMI);
+    LLVM_DEBUG(dbgs() << "Examining: " << *MI);
+    LLVM_DEBUG(dbgs() << "*** Found a common subexpression: " << *CSMI);
 
     // Check if it's profitable to perform this CSE.
     bool DoCSE = true;
@@ -580,7 +580,7 @@
              "Do not CSE physical register defs!");
 
       if (!isProfitableToCSE(NewReg, OldReg, CSMI, MI)) {
-        DEBUG(dbgs() << "*** Not profitable, avoid CSE!\n");
+        LLVM_DEBUG(dbgs() << "*** Not profitable, avoid CSE!\n");
         DoCSE = false;
         break;
       }
@@ -589,7 +589,8 @@
       // within the constraints (register class, bank, or low-level type) of
       // the old instruction.
       if (!MRI->constrainRegAttrs(NewReg, OldReg)) {
-        DEBUG(dbgs() << "*** Not the same register constraints, avoid CSE!\n");
+        LLVM_DEBUG(
+            dbgs() << "*** Not the same register constraints, avoid CSE!\n");
         DoCSE = false;
         break;
       }