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/Target/AMDGPU/AMDGPURewriteOutArguments.cpp b/llvm/lib/Target/AMDGPU/AMDGPURewriteOutArguments.cpp
index 83e56a9..a861762 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPURewriteOutArguments.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPURewriteOutArguments.cpp
@@ -249,8 +249,8 @@
   SmallVector<Argument *, 4> OutArgs;
   for (Argument &Arg : F.args()) {
     if (isOutArgumentCandidate(Arg)) {
-      DEBUG(dbgs() << "Found possible out argument " << Arg
-            << " in function " << F.getName() << '\n');
+      LLVM_DEBUG(dbgs() << "Found possible out argument " << Arg
+                        << " in function " << F.getName() << '\n');
       OutArgs.push_back(&Arg);
     }
   }
@@ -310,7 +310,7 @@
           SI = dyn_cast<StoreInst>(Q.getInst());
 
         if (SI) {
-          DEBUG(dbgs() << "Found out argument store: " << *SI << '\n');
+          LLVM_DEBUG(dbgs() << "Found out argument store: " << *SI << '\n');
           ReplaceableStores.emplace_back(RI, SI);
         } else {
           ThisReplaceable = false;
@@ -328,7 +328,8 @@
         if (llvm::find_if(ValVec,
               [OutArg](const std::pair<Argument *, Value *> &Entry) {
                  return Entry.first == OutArg;}) != ValVec.end()) {
-          DEBUG(dbgs() << "Saw multiple out arg stores" << *OutArg << '\n');
+          LLVM_DEBUG(dbgs()
+                     << "Saw multiple out arg stores" << *OutArg << '\n');
           // It is possible to see stores to the same argument multiple times,
           // but we expect these would have been optimized out already.
           ThisReplaceable = false;
@@ -358,7 +359,7 @@
                                               F.getFunctionType()->params(),
                                               F.isVarArg());
 
-  DEBUG(dbgs() << "Computed new return type: " << *NewRetTy << '\n');
+  LLVM_DEBUG(dbgs() << "Computed new return type: " << *NewRetTy << '\n');
 
   Function *NewFunc = Function::Create(NewFuncTy, Function::PrivateLinkage,
                                        F.getName() + ".body");