[PATCH] D26877: Minor fixes in Loop Strength Reduction

[Evgeny Stupachenko via llvm-commits]

evstupac created this revision.
evstupac added reviewers: sanjoy, jonpa.
evstupac added subscribers: llvm-commits, sanjoy, jonpa.
evstupac set the repository for this revision to rL LLVM.
Herald added a subscriber: mzolotukhin.

The patch contains the following minor fixes:

1. Function renaming: from specific "Condition Instruction" to general "Instruction".
2. Debug print: form address print to Instruction dump.
3. Set count of first register in best registers search.


Repository:
  rL LLVM

https://reviews.llvm.org/D26877

Files:
  lib/Transforms/Scalar/LoopStrengthReduce.cpp


Index: lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1674,7 +1674,7 @@
   SmallPtrSet<Use*, MaxChains> IVIncSet;
 
   void OptimizeShadowIV();
-  bool FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse);
+  bool FindIVUserForInst(Instruction *Inst, IVStrideUse *&InstUse);
   ICmpInst *OptimizeMax(ICmpInst *Cond, IVStrideUse* &CondUse);
   void OptimizeLoopTermCond();
 
@@ -1896,15 +1896,15 @@
   }
 }
 
-/// If Cond has an operand that is an expression of an IV, set the IV user and
+/// If Inst has an operand that is an expression of an IV, set the IV user and
 /// stride information and return true, otherwise return false.
-bool LSRInstance::FindIVUserForCond(ICmpInst *Cond, IVStrideUse *&CondUse) {
+bool LSRInstance::FindIVUserForInst(Instruction *Inst, IVStrideUse *&InstUse) {
   for (IVStrideUse &U : IU)
-    if (U.getUser() == Cond) {
+    if (U.getUser() == Inst) {
       // NOTE: we could handle setcc instructions with multiple uses here, but
       // InstCombine does it as well for simple uses, it's not clear that it
       // occurs enough in real life to handle.
-      CondUse = &U;
+      InstUse = &U;
       return true;
     }
   return false;
@@ -2114,7 +2114,7 @@
     // Search IVUsesByStride to find Cond's IVUse if there is one.
     IVStrideUse *CondUse = nullptr;
     ICmpInst *Cond = cast<ICmpInst>(TermBr->getCondition());
-    if (!FindIVUserForCond(Cond, CondUse))
+    if (!FindIVUserForInst(Cond, CondUse))
       continue;
 
     // If the trip count is computed in terms of a max (due to ScalarEvolution
@@ -2815,7 +2815,7 @@
   DEBUG(dbgs() << "Final Chain: " << *Chain.Incs[0].UserInst << "\n");
 
   for (const IVInc &Inc : Chain) {
-    DEBUG(dbgs() << "        Inc: " << Inc.UserInst << "\n");
+    DEBUG(dbgs() << "        Inc: " << *Inc.UserInst << "\n");
     auto UseI = find(Inc.UserInst->operands(), Inc.IVOperand);
     assert(UseI != Inc.UserInst->op_end() && "cannot find IV operand");
     IVIncSet.insert(UseI);
@@ -4144,9 +4144,10 @@
     for (const SCEV *Reg : RegUses) {
       if (Taken.count(Reg))
         continue;
-      if (!Best)
+      if (!Best) {
         Best = Reg;
-      else {
+        BestNum = RegUses.getUsedByIndices(Reg).count();
+      } else {
         unsigned Count = RegUses.getUsedByIndices(Reg).count();
         if (Count > BestNum) {
           Best = Reg;


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