[SCEVExpander] Simplify cleanup, skip sorting by dominance.

There is no need to sort inserted instructions by dominance, as the
deletion loop still requires RAUW with undef before deleting. Removing
instructions in reverse insertion order should still insure that the
number of uselist updates is kept to a minimum.

4 files changed, 7 insertions, 14 deletions

diff --git a/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h b/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
index efc3cc775e11..608e0975543a 100644
--- a/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
+++ b/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
@@ -504,15 +504,13 @@ private:
 class SCEVExpanderCleaner {
   SCEVExpander &Expander;
 
-  DominatorTree &DT;
-
   /// Indicates whether the result of the expansion is used. If false, the
   /// instructions added during expansion are removed.
   bool ResultUsed;
 
 public:
-  SCEVExpanderCleaner(SCEVExpander &Expander, DominatorTree &DT)
-      : Expander(Expander), DT(DT), ResultUsed(false) {}
+  SCEVExpanderCleaner(SCEVExpander &Expander)
+      : Expander(Expander), ResultUsed(false) {}
 
   ~SCEVExpanderCleaner() { cleanup(); }
 
diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index 5d00fa56e888..35ba4e2b4032 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -1117,7 +1117,7 @@ bool LoopIdiomRecognize::processLoopStridedStore(
   BasicBlock *Preheader = CurLoop->getLoopPreheader();
   IRBuilder<> Builder(Preheader->getTerminator());
   SCEVExpander Expander(*SE, *DL, "loop-idiom");
-  SCEVExpanderCleaner ExpCleaner(Expander, *DT);
+  SCEVExpanderCleaner ExpCleaner(Expander);
 
   Type *DestInt8PtrTy = Builder.getInt8PtrTy(DestAS);
   Type *IntIdxTy = DL->getIndexType(DestPtr->getType());
@@ -1328,7 +1328,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(
   IRBuilder<> Builder(Preheader->getTerminator());
   SCEVExpander Expander(*SE, *DL, "loop-idiom");
 
-  SCEVExpanderCleaner ExpCleaner(Expander, *DT);
+  SCEVExpanderCleaner ExpCleaner(Expander);
 
   bool Changed = false;
   const SCEV *StrStart = StoreEv->getStart();
diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
index 3b1e160a8567..d60462329d42 100644
--- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
@@ -2742,13 +2742,8 @@ void SCEVExpanderCleaner::cleanup() {
   // Remove sets with value handles.
   Expander.clear();
 
-  // Sort so that earlier instructions do not dominate later instructions.
-  stable_sort(InsertedInstructions, [this](Instruction *A, Instruction *B) {
-    return DT.dominates(B, A);
-  });
   // Remove all inserted instructions.
-  for (Instruction *I : InsertedInstructions) {
-
+  for (Instruction *I : reverse(InsertedInstructions)) {
 #ifndef NDEBUG
     assert(all_of(I->users(),
                   [&InsertedSet](Value *U) {
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index a61efbf2460d..a37dba1ac65e 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2065,8 +2065,8 @@ public:
   /// Remove the created SCEV & memory runtime check blocks & instructions, if
   /// unused.
   ~GeneratedRTChecks() {
-    SCEVExpanderCleaner SCEVCleaner(SCEVExp, *DT);
-    SCEVExpanderCleaner MemCheckCleaner(MemCheckExp, *DT);
+    SCEVExpanderCleaner SCEVCleaner(SCEVExp);
+    SCEVExpanderCleaner MemCheckCleaner(MemCheckExp);
     if (!SCEVCheckCond)
       SCEVCleaner.markResultUsed();