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