[DebugInfo] Examine all uses of isDebugValue() for debug instructions.

Because we create a new kind of debug instruction, DBG_LABEL, we need to
check all passes which use isDebugValue() to check MachineInstr is debug
instruction or not. When expelling debug instructions, we should expel
both DBG_VALUE and DBG_LABEL. So, I create a new function,
isDebugInstr(), in MachineInstr to check whether the MachineInstr is
debug instruction or not.

This patch has no new test case. I have run regression test and there is
no difference in regression test.

Differential Revision: https://reviews.llvm.org/D45342

Patch by Hsiangkai Wang.

llvm-svn: 331844
diff --git a/llvm/lib/Target/Hexagon/HexagonBlockRanges.cpp b/llvm/lib/Target/Hexagon/HexagonBlockRanges.cpp
index 8153c49..2fb30df 100644
--- a/llvm/lib/Target/Hexagon/HexagonBlockRanges.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonBlockRanges.cpp
@@ -160,7 +160,7 @@
   IndexType Idx = IndexType::First;
   First = Idx;
   for (auto &In : B) {
-    if (In.isDebugValue())
+    if (In.isDebugInstr())
       continue;
     assert(getIndex(&In) == IndexType::None && "Instruction already in map");
     Map.insert(std::make_pair(Idx, &In));
@@ -314,7 +314,7 @@
   RegisterSet Defs, Clobbers;
 
   for (auto &In : B) {
-    if (In.isDebugValue())
+    if (In.isDebugInstr())
       continue;
     IndexType Index = IndexMap.getIndex(&In);
     // Process uses first.