[TableGen] Inline a helper function that didn't seem necessary. NFC (#123440)

The function called find_if and converted the iterator to an index.
The caller then had to check the index being non-zero to know if the
find succeeded.

Seems better to just do the find and distance in the caller.

Author: topperc

llvm/utils/TableGen/Common/CodeGenSchedule.cpp

@@ -809,30 +809,21 @@ void CodeGenSchedModels::expandRWSeqForProc(
   }
 }
 
-// Find the existing SchedWrite that models this sequence of writes.
-unsigned CodeGenSchedModels::findRWForSequence(ArrayRef<unsigned> Seq,
-                                               bool IsRead) {
-  std::vector<CodeGenSchedRW> &RWVec = IsRead ? SchedReads : SchedWrites;
-
-  auto I = find_if(RWVec, [Seq](CodeGenSchedRW &RW) {
-    return ArrayRef(RW.Sequence) == Seq;
-  });
-  // Index zero reserved for invalid RW.
-  return I == RWVec.end() ? 0 : std::distance(RWVec.begin(), I);
-}
-
 /// Add this ReadWrite if it doesn't already exist.
 unsigned CodeGenSchedModels::findOrInsertRW(ArrayRef<unsigned> Seq,
                                             bool IsRead) {
   assert(!Seq.empty() && "cannot insert empty sequence");
   if (Seq.size() == 1)
     return Seq.back();
 
-  unsigned Idx = findRWForSequence(Seq, IsRead);
-  if (Idx)
-    return Idx;
-
   std::vector<CodeGenSchedRW> &RWVec = IsRead ? SchedReads : SchedWrites;
+
+  auto I = find_if(RWVec, [Seq](CodeGenSchedRW &RW) {
+    return ArrayRef(RW.Sequence) == Seq;
+  });
+  if (I != RWVec.end())
+    return std::distance(RWVec.begin(), I);
+
   unsigned RWIdx = RWVec.size();
   CodeGenSchedRW SchedRW(RWIdx, IsRead, Seq, genRWName(Seq, IsRead));
   RWVec.push_back(SchedRW);

llvm/utils/TableGen/Common/CodeGenSchedule.h

@@ -592,7 +592,6 @@ class CodeGenSchedModels {
   void collectSchedRW();
 
   std::string genRWName(ArrayRef<unsigned> Seq, bool IsRead);
-  unsigned findRWForSequence(ArrayRef<unsigned> Seq, bool IsRead);
 
   void collectSchedClasses();