[llvm] 1ce01b7 - [SCEVExpander] Simplify cleanup, skip sorting by dominance.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2022-01-09T18:38:41Z
New Revision: 1ce01b7dfe8247c25b25e0ed44b7f1e41599bb43

URL: https://github.com/llvm/llvm-project/commit/1ce01b7dfe8247c25b25e0ed44b7f1e41599bb43
DIFF: https://github.com/llvm/llvm-project/commit/1ce01b7dfe8247c25b25e0ed44b7f1e41599bb43.diff

LOG: [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.

Added: 
    

Modified: 
    llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
    llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
    llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp
    llvm/lib/Transforms/Vectorize/LoopVectorize.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h b/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
index efc3cc775e116..608e0975543a5 100644
--- a/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
+++ b/llvm/include/llvm/Transforms/Utils/ScalarEvolutionExpander.h
@@ -504,15 +504,13 @@ class SCEVExpander : public SCEVVisitor<SCEVExpander, Value *> {
 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 5d00fa56e888b..35ba4e2b4032d 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 3b1e160a85678..d60462329d422 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 a61efbf2460d2..a37dba1ac65e3 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2065,8 +2065,8 @@ class GeneratedRTChecks {
   /// 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();