[InstCombine] Pass RPOT to InstCombiner (NFC)

To make use of it in a followup change.

Author: nikic

llvm/include/llvm/Transforms/InstCombine/InstCombiner.h

@@ -84,6 +84,8 @@ class LLVM_LIBRARY_VISIBILITY InstCombiner {
   // combining and will be updated to reflect any changes.
   LoopInfo *LI;
 
+  ReversePostOrderTraversal<BasicBlock *> &RPOT;
+
   bool MadeIRChange = false;
 
   /// Edges that are known to never be taken.
@@ -98,12 +100,13 @@ class LLVM_LIBRARY_VISIBILITY InstCombiner {
                TargetLibraryInfo &TLI, TargetTransformInfo &TTI,
                DominatorTree &DT, OptimizationRemarkEmitter &ORE,
                BlockFrequencyInfo *BFI, BranchProbabilityInfo *BPI,
-               ProfileSummaryInfo *PSI, const DataLayout &DL, LoopInfo *LI)
+               ProfileSummaryInfo *PSI, const DataLayout &DL, LoopInfo *LI,
+               ReversePostOrderTraversal<BasicBlock *> &RPOT)
       : TTI(TTI), Builder(Builder), Worklist(Worklist),
         MinimizeSize(MinimizeSize), AA(AA), AC(AC), TLI(TLI), DT(DT), DL(DL),
         SQ(DL, &TLI, &DT, &AC, nullptr, /*UseInstrInfo*/ true,
            /*CanUseUndef*/ true, &DC),
-        ORE(ORE), BFI(BFI), BPI(BPI), PSI(PSI), LI(LI) {}
+        ORE(ORE), BFI(BFI), BPI(BPI), PSI(PSI), LI(LI), RPOT(RPOT) {}
 
   virtual ~InstCombiner() = default;
 

llvm/lib/Transforms/InstCombine/InstCombineInternal.h

@@ -66,15 +66,15 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
                    TargetLibraryInfo &TLI, TargetTransformInfo &TTI,
                    DominatorTree &DT, OptimizationRemarkEmitter &ORE,
                    BlockFrequencyInfo *BFI, BranchProbabilityInfo *BPI,
-                   ProfileSummaryInfo *PSI, const DataLayout &DL, LoopInfo *LI)
+                   ProfileSummaryInfo *PSI, const DataLayout &DL, LoopInfo *LI,
+                   ReversePostOrderTraversal<BasicBlock *> &RPOT)
       : InstCombiner(Worklist, Builder, MinimizeSize, AA, AC, TLI, TTI, DT, ORE,
-                     BFI, BPI, PSI, DL, LI) {}
+                     BFI, BPI, PSI, DL, LI, RPOT) {}
 
   virtual ~InstCombinerImpl() = default;
 
   /// Perform early cleanup and prepare the InstCombine worklist.
-  bool prepareWorklist(Function &F,
-                       ReversePostOrderTraversal<BasicBlock *> &RPOT);
+  bool prepareWorklist(Function &F);
 
   /// Run the combiner over the entire worklist until it is empty.
   ///

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -5234,8 +5234,7 @@ class AliasScopeTracker {
 /// them to the worklist (this significantly speeds up instcombine on code where
 /// many instructions are dead or constant).  Additionally, if we find a branch
 /// whose condition is a known constant, we only visit the reachable successors.
-bool InstCombinerImpl::prepareWorklist(
-    Function &F, ReversePostOrderTraversal<BasicBlock *> &RPOT) {
+bool InstCombinerImpl::prepareWorklist(Function &F) {
   bool MadeIRChange = false;
   SmallPtrSet<BasicBlock *, 32> LiveBlocks;
   SmallVector<Instruction *, 128> InstrsForInstructionWorklist;
@@ -5417,9 +5416,9 @@ static bool combineInstructionsOverFunction(
                       << F.getName() << "\n");
 
     InstCombinerImpl IC(Worklist, Builder, F.hasMinSize(), AA, AC, TLI, TTI, DT,
-                        ORE, BFI, BPI, PSI, DL, LI);
+                        ORE, BFI, BPI, PSI, DL, LI, RPOT);
     IC.MaxArraySizeForCombine = MaxArraySize;
-    bool MadeChangeInThisIteration = IC.prepareWorklist(F, RPOT);
+    bool MadeChangeInThisIteration = IC.prepareWorklist(F);
     MadeChangeInThisIteration |= IC.run();
     if (!MadeChangeInThisIteration)
       break;