Add enum values to CodeGenOpt::Level

[sbc100]

Summary

The absolute values of this enum are important at least in that
they get printed by SelectionDAGISel. e.g:

`Before: -O2 ; After: -O0`

[sbc100]

revert

[aheejin]

include/llvm/Support/CodeGen.h

55

Looks like not clang-formatted

[sbc100]

• clang format

include/llvm/Support/CodeGen.h

enum Model {
       InitialExec,
       LocalExec
     };
   }
 
   // Code generation optimization level.
   namespace CodeGenOpt {
     enum Level {
-      None,        // -O0
-      Less,        // -O1
-      Default,     // -O2, -Os
-      Aggressive   // -O3
+      None=0,        // -O0
+      Less=1,        // -O1
+      Default=2,     // -O2, -Os
+      Aggressive=3   // -O3
     };
   }
 
   // Specify effect of frame pointer elimination optimization.
   namespace FramePointer {
     enum FP {All, NonLeaf, None};
   }
 
 }  // end llvm namespace
 
 #endif

lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

class OptLevelChanger {
     SelectionDAGISel &IS;
     CodeGenOpt::Level SavedOptLevel;
     bool SavedFastISel;
 
   public:
     OptLevelChanger(SelectionDAGISel &ISel,
                     CodeGenOpt::Level NewOptLevel) : IS(ISel) {
       SavedOptLevel = IS.OptLevel;
-      if (NewOptLevel == SavedOptLevel)
-        return;
+      //if (NewOptLevel == SavedOptLevel)
+        //return;
       IS.OptLevel = NewOptLevel;
       IS.TM.setOptLevel(NewOptLevel);
       LLVM_DEBUG(dbgs() << "\nChanging optimization level for Function "
                         << IS.MF->getFunction().getName() << "\n");
       LLVM_DEBUG(dbgs() << "\tBefore: -O" << SavedOptLevel << " ; After: -O"
                         << NewOptLevel << "\n");
       SavedFastISel = IS.TM.Options.EnableFastISel;
       if (NewOptLevel == CodeGenOpt::None) {
         IS.TM.setFastISel(IS.TM.getO0WantsFastISel());
         LLVM_DEBUG(
             dbgs() << "\tFastISel is "
                    << (IS.TM.Options.EnableFastISel ? "enabled" : "disabled")
                    << "\n");
       }
     }
 
     ~OptLevelChanger() {
-      if (IS.OptLevel == SavedOptLevel)
-        return;
+      //if (IS.OptLevel == SavedOptLevel)
+        //return;
       LLVM_DEBUG(dbgs() << "\nRestoring optimization level for Function "
                         << IS.MF->getFunction().getName() << "\n");
       LLVM_DEBUG(dbgs() << "\tBefore: -O" << IS.OptLevel << " ; After: -O"
                         << SavedOptLevel << "\n");
       IS.OptLevel = SavedOptLevel;
       IS.TM.setOptLevel(SavedOptLevel);
       IS.TM.setFastISel(SavedFastISel);
     }