SimplifyCFG: Collect lookup table statistics at creation

Since the SwitchReplacement is created before we decide to replace the
switch, only increase the table counters when we actually create them.

Author: OutOfCache

llvm/lib/Transforms/Utils/SimplifyCFG.cpp

@@ -6619,7 +6619,6 @@ SwitchReplacement::SwitchReplacement(
         (void)M.smul_ov(APInt(M.getBitWidth(), TableSize - 1), MayWrap);
       LinearMapValWrapped = NonMonotonic || MayWrap;
       Kind = LinearMapKind;
-      ++NumLinearMaps;
       return;
     }
   }
@@ -6639,7 +6638,6 @@ SwitchReplacement::SwitchReplacement(
     BitMap = ConstantInt::get(M.getContext(), TableInt);
     BitMapElementTy = IT;
     Kind = BitMapKind;
-    ++NumBitMaps;
     return;
   }
 
@@ -6656,6 +6654,7 @@ Value *SwitchReplacement::replaceSwitch(Value *Index, IRBuilder<> &Builder,
   case SingleValueKind:
     return SingleValue;
   case LinearMapKind: {
+    ++NumLinearMaps;
     // Derive the result value from the input value.
     Value *Result = Builder.CreateIntCast(Index, LinearMultiplier->getType(),
                                           false, "switch.idx.cast");
@@ -6671,6 +6670,7 @@ Value *SwitchReplacement::replaceSwitch(Value *Index, IRBuilder<> &Builder,
     return Result;
   }
   case BitMapKind: {
+    ++NumBitMaps;
     // Type of the bitmap (e.g. i59).
     IntegerType *MapTy = BitMap->getIntegerType();
 
@@ -6693,6 +6693,7 @@ Value *SwitchReplacement::replaceSwitch(Value *Index, IRBuilder<> &Builder,
     return Builder.CreateTrunc(DownShifted, BitMapElementTy, "switch.masked");
   }
   case LookupTableKind: {
+    ++NumLookupTables;
     auto *Table =
         new GlobalVariable(*Func->getParent(), Initializer->getType(),
                            /*isConstant=*/true, GlobalVariable::PrivateLinkage,
@@ -7261,7 +7262,6 @@ static bool simplifySwitchLookup(SwitchInst *SI, IRBuilder<> &Builder,
   if (DTU)
     DTU->applyUpdates(Updates);
 
-  ++NumLookupTables;
   if (NeedMask)
     ++NumLookupTablesHoles;
   return true;