[LVI] Remove count/erase idiom in favor of checking result value of e…

…rase

Minor compile time win.  Avoids an additional O(N) scan in the case where we are removing an element and costs nothing when we aren't.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@290768 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Analysis/LazyValueInfo.cpp

@@ -462,8 +462,7 @@ void LazyValueInfoCache::eraseValue(Value *V) {
   SmallVector<AssertingVH<BasicBlock>, 4> ToErase;
   for (auto &I : OverDefinedCache) {
     SmallPtrSetImpl<Value *> &ValueSet = I.second;
-    if (ValueSet.count(V))
-      ValueSet.erase(V);
+    ValueSet.erase(V);
     if (ValueSet.empty())
       ToErase.push_back(I.first);
   }
@@ -533,12 +532,9 @@ void LazyValueInfoCache::threadEdgeImpl(BasicBlock *OldSucc,
 
     bool changed = false;
     for (Value *V : ValsToClear) {
-      // TODO: count and erase can be converted to a find/erase(itr) pattern
-      if (!ValueSet.count(V))
+      if (!ValueSet.erase(V))
         continue;
 
-      ValueSet.erase(V);
-
       // If we removed anything, then we potentially need to update
       // blocks successors too.
       changed = true;