[PATCH] D131488: [TypePromotion] Don't delete Insns when iterating

[Andre Vieira via Phabricator via llvm-commits]

avieira created this revision.
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Hi,

This patch changes the way we delete Insns in TypePromotion, such that we don't do it while iterating over the same BB we are deleting from. This hasn't been an issue before, I suspect because when searching up from icmp's we only delete Insns that are before the current Insn or in other BBs, but with the changes proposed in D111237 <https://reviews.llvm.org/D111237> it will be an issue.


https://reviews.llvm.org/D131488

Files:
  llvm/lib/CodeGen/TypePromotion.cpp


Index: llvm/lib/CodeGen/TypePromotion.cpp
===================================================================
--- llvm/lib/CodeGen/TypePromotion.cpp
+++ llvm/lib/CodeGen/TypePromotion.cpp
@@ -106,9 +106,9 @@
   SetVector<Value *> &Sources;
   SetVector<Instruction *> &Sinks;
   SmallPtrSetImpl<Instruction *> &SafeWrap;
+  SmallPtrSetImpl<Instruction *> &InstsToRemove;
   IntegerType *ExtTy = nullptr;
   SmallPtrSet<Value *, 8> NewInsts;
-  SmallPtrSet<Instruction *, 4> InstsToRemove;
   DenseMap<Value *, SmallVector<Type *, 4>> TruncTysMap;
   SmallPtrSet<Value *, 8> Promoted;
 
@@ -120,12 +120,12 @@
   void Cleanup();
 
 public:
-  IRPromoter(LLVMContext &C, unsigned Width,
-             SetVector<Value *> &visited, SetVector<Value *> &sources,
-             SetVector<Instruction *> &sinks,
-             SmallPtrSetImpl<Instruction *> &wrap)
-      : Ctx(C), PromotedWidth(Width), Visited(visited),
-        Sources(sources), Sinks(sinks), SafeWrap(wrap) {
+  IRPromoter(LLVMContext &C, unsigned Width, SetVector<Value *> &visited,
+             SetVector<Value *> &sources, SetVector<Instruction *> &sinks,
+             SmallPtrSetImpl<Instruction *> &wrap,
+             SmallPtrSetImpl<Instruction *> &instsToRemove)
+      : Ctx(C), PromotedWidth(Width), Visited(visited), Sources(sources),
+        Sinks(sinks), SafeWrap(wrap), InstsToRemove(instsToRemove) {
     ExtTy = IntegerType::get(Ctx, PromotedWidth);
   }
 
@@ -139,6 +139,7 @@
   SmallPtrSet<Value *, 16> AllVisited;
   SmallPtrSet<Instruction *, 8> SafeToPromote;
   SmallPtrSet<Instruction *, 4> SafeWrap;
+  SmallPtrSet<Instruction *, 4> InstsToRemove;
 
   // Does V have the same size result type as TypeSize.
   bool EqualTypeSize(Value *V);
@@ -602,7 +603,6 @@
   for (auto *I : InstsToRemove) {
     LLVM_DEBUG(dbgs() << "IR Promotion: Removing " << *I << "\n");
     I->dropAllReferences();
-    I->eraseFromParent();
   }
 }
 
@@ -874,7 +874,7 @@
     return false;
 
   IRPromoter Promoter(*Ctx, PromotedWidth, CurrentVisited, Sources, Sinks,
-                      SafeWrap);
+                      SafeWrap, InstsToRemove);
   Promoter.Mutate();
   return true;
 }
@@ -940,6 +940,11 @@
         }
       }
     }
+    if (!InstsToRemove.empty()) {
+      for (auto *I : InstsToRemove)
+        I->eraseFromParent();
+      InstsToRemove.clear();
+    }
   }
 
   AllVisited.clear();


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