[llvm] 18a5bd7 - [InstCombine] Add droppable users back to worklist (NFCI)

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2023-05-23T17:01:23+02:00
New Revision: 18a5bd7a9539464c9818f9c73c7ce6ccf0522249

URL: https://github.com/llvm/llvm-project/commit/18a5bd7a9539464c9818f9c73c7ce6ccf0522249
DIFF: https://github.com/llvm/llvm-project/commit/18a5bd7a9539464c9818f9c73c7ce6ccf0522249.diff

LOG: [InstCombine] Add droppable users back to worklist (NFCI)

When sinking and users are dropped, add the using instructions
to the worklist, as they can likely be removed as well.

This should be NFC apart from worklist order effects.

Added: 
    

Modified: 
    llvm/lib/Transforms/InstCombine/InstCombineInternal.h
    llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

Removed: 
    


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diff  --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index 2486be77ebab..0f2e516e2f91 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -653,6 +653,8 @@ class LLVM_LIBRARY_VISIBILITY InstCombinerImpl final
   Instruction *SimplifyAnyMemSet(AnyMemSetInst *MI);
 
   Value *EvaluateInDifferentType(Value *V, Type *Ty, bool isSigned);
+
+  bool tryToSinkInstruction(Instruction *I, BasicBlock *DestBlock);
 };
 
 class Negator final {

diff  --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index b1f4e9f8e4f2..8c10fe96aaf8 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -3475,8 +3475,8 @@ static bool SoleWriteToDeadLocal(Instruction *I, TargetLibraryInfo &TLI) {
 /// beginning of DestBlock, which can only happen if it's safe to move the
 /// instruction past all of the instructions between it and the end of its
 /// block.
-static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock,
-                                 TargetLibraryInfo &TLI) {
+bool InstCombinerImpl::tryToSinkInstruction(Instruction *I,
+                                            BasicBlock *DestBlock) {
   BasicBlock *SrcBlock = I->getParent();
 
   // Cannot move control-flow-involving, volatile loads, vaarg, etc.
@@ -3523,10 +3523,13 @@ static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock,
         return false;
   }
 
-  I->dropDroppableUses([DestBlock](const Use *U) {
-    if (auto *I = dyn_cast<Instruction>(U->getUser()))
-      return I->getParent() != DestBlock;
-    return true;
+  I->dropDroppableUses([&](const Use *U) {
+    auto *I = dyn_cast<Instruction>(U->getUser());
+    if (I && I->getParent() != DestBlock) {
+      Worklist.add(I);
+      return true;
+    }
+    return false;
   });
   /// FIXME: We could remove droppable uses that are not dominated by
   /// the new position.
@@ -3699,7 +3702,7 @@ bool InstCombinerImpl::run() {
     if (OptBB) {
       auto *UserParent = *OptBB;
       // Okay, the CFG is simple enough, try to sink this instruction.
-      if (TryToSinkInstruction(I, UserParent, TLI)) {
+      if (tryToSinkInstruction(I, UserParent)) {
         LLVM_DEBUG(dbgs() << "IC: Sink: " << *I << '\n');
         MadeIRChange = true;
         // We'll add uses of the sunk instruction below, but since