[Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all of the header #include lines, lib/Transforms/...
edition.

This one is tricky for two reasons. We again have a couple of passes
that define something else before the includes as well. I've sunk their
name macros with the DEBUG_TYPE.

Also, InstCombine contains headers that need DEBUG_TYPE, so now those
headers #define and #undef DEBUG_TYPE around their code, leaving them
well formed modular headers. Fixing these headers was a large motivation
for all of these changes, as "leaky" macros of this form are hard on the
modules implementation.

llvm-svn: 206844
diff --git a/llvm/lib/Transforms/InstCombine/InstCombine.h b/llvm/lib/Transforms/InstCombine/InstCombine.h
index 4ee2f59..1a9dcdd 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombine.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombine.h
@@ -20,6 +20,8 @@
 #include "llvm/Pass.h"
 #include "llvm/Transforms/Utils/SimplifyLibCalls.h"
 
+#define DEBUG_TYPE "instcombine"
+
 namespace llvm {
   class CallSite;
   class DataLayout;
@@ -394,8 +396,8 @@
   Value *Descale(Value *Val, APInt Scale, bool &NoSignedWrap);
 };
 
-
-
 } // end namespace llvm.
 
+#undef DEBUG_TYPE
+
 #endif