[SCEV][NFC] Remove redundant params from isAvailableAtLoopEntry

[mkazantsev]

Summary

Params DT and LI are redundant, because these values are contained in fields anyways.

include/llvm/Analysis/ScalarEvolution.h

public:
 
   /// Return true if the value of the given SCEV is unchanging in the
   /// specified loop.
   bool isLoopInvariant(const SCEV *S, const Loop *L);
 
   /// Determine if the SCEV can be evaluated at loop's entry. It is true if it
   /// doesn't depend on a SCEVUnknown of an instruction which is dominated by
   /// the header of loop L.
-  bool isAvailableAtLoopEntry(const SCEV *S, const Loop *L, DominatorTree &DT,
-                              LoopInfo &LI);
+  bool isAvailableAtLoopEntry(const SCEV *S, const Loop *L);
 
   /// Return true if the given SCEV changes value in a known way in the
   /// specified loop.  This property being true implies that the value is
   /// variant in the loop AND that we can emit an expression to compute the
   /// value of the expression at any particular loop iteration.
   bool hasComputableLoopEvolution(const SCEV *S, const Loop *L);
 
   /// Return the "disposition" of the given SCEV with respect to the given

lib/Analysis/ScalarEvolution.cpp

if (!(SignOrUnsignWrap & SCEV::FlagNUW)) {
       if (NUWRegion.contains(SE->getUnsignedRange(Ops[1])))
         Flags = ScalarEvolution::setFlags(Flags, SCEV::FlagNUW);
     }
   }
 
   return Flags;
 }
 
-bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L,
-                                             DominatorTree &DT, LoopInfo &LI) {
+bool ScalarEvolution::isAvailableAtLoopEntry(const SCEV *S, const Loop *L) {
   if (!isLoopInvariant(S, L))
     return false;
   // If a value depends on a SCEVUnknown which is defined after the loop, we
   // conservatively assume that we cannot calculate it at the loop's entry.
   struct FindDominatedSCEVUnknown {
     bool Found = false;
     const Loop *L;
     DominatorTree &DT;
#endif
   // Scan over all recurrences, trying to fold loop invariants into them.
   for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
     // Scan all of the other operands to this add and add them to the vector if
     // they are loop invariant w.r.t. the recurrence.
     SmallVector<const SCEV *, 8> LIOps;
     const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
     const Loop *AddRecLoop = AddRec->getLoop();
     for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-      if (isAvailableAtLoopEntry(Ops[i], AddRecLoop, DT, LI)) {
+      if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) {
         LIOps.push_back(Ops[i]);
         Ops.erase(Ops.begin()+i);
         --i; --e;
       }
 
     // If we found some loop invariants, fold them into the recurrence.
     if (!LIOps.empty()) {
       //  NLI + LI + {Start,+,Step}  -->  NLI + {LI+Start,+,Step}
#endif
   // Scan over all recurrences, trying to fold loop invariants into them.
   for (; Idx < Ops.size() && isa<SCEVAddRecExpr>(Ops[Idx]); ++Idx) {
     // Scan all of the other operands to this mul and add them to the vector if
     // they are loop invariant w.r.t. the recurrence.
     SmallVector<const SCEV *, 8> LIOps;
     const SCEVAddRecExpr *AddRec = cast<SCEVAddRecExpr>(Ops[Idx]);
     const Loop *AddRecLoop = AddRec->getLoop();
     for (unsigned i = 0, e = Ops.size(); i != e; ++i)
-      if (isAvailableAtLoopEntry(Ops[i], AddRecLoop, DT, LI)) {
+      if (isAvailableAtLoopEntry(Ops[i], AddRecLoop)) {
         LIOps.push_back(Ops[i]);
         Ops.erase(Ops.begin()+i);
         --i; --e;
       }
 
     // If we found some loop invariants, fold them into the recurrence.
     if (!LIOps.empty()) {
       //  NLI * LI * {Start,+,Step}  -->  NLI * {LI*Start,+,LI*Step}