Revert commit 158979 (dyatkovskiy) since it is causing several buildbots to

fail.  Original commit message:

Performance optimizations:
- SwitchInst: case values stored separately from Operands List. It allows to make faster access to individual case value numbers or ranges.
- Optimized IntItem, added APInt value caching.
- Optimized IntegersSubsetGeneric: added optimizations for cases when subset is single number or when subset consists from single numbers only.

On my machine these optimizations gave about 4-6% of compile-time improvement.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158986 91177308-0d34-0410-b5e6-96231b3b80d8

lib/VMCore/Instructions.cpp

@@ -3158,7 +3158,6 @@ SwitchInst::SwitchInst(const SwitchInst &SI)
     OL[i] = InOL[i];
     OL[i+1] = InOL[i+1];
   }
-  TheSubsets = SI.TheSubsets;
   SubclassOptionalData = SI.SubclassOptionalData;
 }
 
@@ -3187,11 +3186,8 @@ void SwitchInst::addCase(IntegersSubset& OnVal, BasicBlock *Dest) {
   // Initialize some new operands.
   assert(OpNo+1 < ReservedSpace && "Growing didn't work!");
   NumOperands = OpNo+2;
-
-  SubsetsIt TheSubsetsIt = TheSubsets.insert(TheSubsets.end(), OnVal);
-  
-  CaseIt Case(this, NewCaseIdx, TheSubsetsIt);
-  Case.updateCaseValueOperand(OnVal);
+  CaseIt Case(this, NewCaseIdx);
+  Case.setValueEx(OnVal);
   Case.setSuccessor(Dest);
 }
 
@@ -3214,11 +3210,6 @@ void SwitchInst::removeCase(CaseIt i) {
   // Nuke the last value.
   OL[NumOps-2].set(0);
   OL[NumOps-2+1].set(0);
-
-  // Do the same with TheCases collection:
-  *i.SubsetIt = TheSubsets.back();
-  TheSubsets.pop_back();
-  
   NumOperands = NumOps-2;
 }