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/SIShrinkInstructions.cpp b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
index 33fd5a3..3c4c3ba 100644
--- a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
+++ b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
@@ -495,7 +495,7 @@
       }
 
       // We can shrink this instruction
-      DEBUG(dbgs() << "Shrinking " << MI);
+      LLVM_DEBUG(dbgs() << "Shrinking " << MI);
 
       MachineInstrBuilder Inst32 =
           BuildMI(MBB, I, MI.getDebugLoc(), TII->get(Op32));
@@ -539,9 +539,7 @@
       MI.eraseFromParent();
       foldImmediates(*Inst32, TII, MRI);
 
-      DEBUG(dbgs() << "e32 MI = " << *Inst32 << '\n');
-
-
+      LLVM_DEBUG(dbgs() << "e32 MI = " << *Inst32 << '\n');
     }
   }
   return false;