[Mips] Fix some Clang-tidy modernize-use-using and Include What You Use warnings; other minor fixes (NFC).

llvm-svn: 309993
diff --git a/llvm/lib/Target/Mips/MipsFastISel.cpp b/llvm/lib/Target/Mips/MipsFastISel.cpp
index f79cb0e..bec0ae6 100644
--- a/llvm/lib/Target/Mips/MipsFastISel.cpp
+++ b/llvm/lib/Target/Mips/MipsFastISel.cpp
@@ -1,4 +1,4 @@
-//===-- MipsFastISel.cpp - Mips FastISel implementation -------------------===//
+//===- MipsFastISel.cpp - Mips FastISel implementation --------------------===//
 //
 // The LLVM Compiler Infrastructure
 //
@@ -69,7 +69,6 @@
 #include <algorithm>
 #include <cassert>
 #include <cstdint>
-#include <new>
 
 #define DEBUG_TYPE "mips-fastisel"
 
@@ -82,7 +81,7 @@
   // All possible address modes.
   class Address {
   public:
-    typedef enum { RegBase, FrameIndexBase } BaseKind;
+    using BaseKind = enum { RegBase, FrameIndexBase };
 
   private:
     BaseKind Kind = RegBase;
@@ -231,7 +230,6 @@
 
   // for some reason, this default is not generated by tablegen
   // so we explicitly generate it here.
-  //
   unsigned fastEmitInst_riir(uint64_t inst, const TargetRegisterClass *RC,
                              unsigned Op0, bool Op0IsKill, uint64_t imm1,
                              uint64_t imm2, unsigned Op3, bool Op3IsKill) {
@@ -629,6 +627,7 @@
     return true;
   return false;
 }
+
 // Because of how EmitCmp is called with fast-isel, you can
 // end up with redundant "andi" instructions after the sequences emitted below.
 // We should try and solve this issue in the future.
@@ -937,10 +936,8 @@
   return true;
 }
 
-//
 // This can cause a redundant sltiu to be generated.
 // FIXME: try and eliminate this in a future patch.
-//
 bool MipsFastISel::selectBranch(const Instruction *I) {
   const BranchInst *BI = cast<BranchInst>(I);
   MachineBasicBlock *BrBB = FuncInfo.MBB;