[CodeGenPrepare] Don't simplify incomplete expression tree in AddrModeCombine

llvm/lib/CodeGen/CodeGenPrepare.cpp

@@ -4030,16 +4030,13 @@ bool PhiNodeSetIterator::operator!=(const PhiNodeSetIterator &RHS) const {
 /// if it is simplified.
 class SimplificationTracker {
   DenseMap<Value *, Value *> Storage;
-  const SimplifyQuery &SQ;
   // Tracks newly created Phi nodes. The elements are iterated by insertion
   // order.
   PhiNodeSet AllPhiNodes;
   // Tracks newly created Select nodes.
   SmallPtrSet<SelectInst *, 32> AllSelectNodes;
 
 public:
-  SimplificationTracker(const SimplifyQuery &sq) : SQ(sq) {}
-
   Value *Get(Value *V) {
     do {
       auto SV = Storage.find(V);
@@ -4049,30 +4046,6 @@ class SimplificationTracker {
     } while (true);
   }
 
-  Value *Simplify(Value *Val) {
-    SmallVector<Value *, 32> WorkList;
-    SmallPtrSet<Value *, 32> Visited;
-    WorkList.push_back(Val);
-    while (!WorkList.empty()) {
-      auto *P = WorkList.pop_back_val();
-      if (!Visited.insert(P).second)
-        continue;
-      if (auto *PI = dyn_cast<Instruction>(P))
-        if (Value *V = simplifyInstruction(cast<Instruction>(PI), SQ)) {
-          for (auto *U : PI->users())
-            WorkList.push_back(cast<Value>(U));
-          Put(PI, V);
-          PI->replaceAllUsesWith(V);
-          if (auto *PHI = dyn_cast<PHINode>(PI))
-            AllPhiNodes.erase(PHI);
-          if (auto *Select = dyn_cast<SelectInst>(PI))
-            AllSelectNodes.erase(Select);
-          PI->eraseFromParent();
-        }
-    }
-    return Get(Val);
-  }
-
   void Put(Value *From, Value *To) { Storage.insert({From, To}); }
 
   void ReplacePhi(PHINode *From, PHINode *To) {
@@ -4133,8 +4106,7 @@ class AddressingModeCombiner {
   /// Common Type for all different fields in addressing modes.
   Type *CommonType = nullptr;
 
-  /// SimplifyQuery for simplifyInstruction utility.
-  const SimplifyQuery &SQ;
+  const DataLayout &DL;
 
   /// Original Address.
   Value *Original;
@@ -4143,8 +4115,8 @@ class AddressingModeCombiner {
   Value *CommonValue = nullptr;
 
 public:
-  AddressingModeCombiner(const SimplifyQuery &_SQ, Value *OriginalValue)
-      : SQ(_SQ), Original(OriginalValue) {}
+  AddressingModeCombiner(const DataLayout &DL, Value *OriginalValue)
+      : DL(DL), Original(OriginalValue) {}
 
   ~AddressingModeCombiner() { eraseCommonValueIfDead(); }
 
@@ -4256,7 +4228,7 @@ class AddressingModeCombiner {
     // Keep track of keys where the value is null. We will need to replace it
     // with constant null when we know the common type.
     SmallVector<Value *, 2> NullValue;
-    Type *IntPtrTy = SQ.DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
+    Type *IntPtrTy = DL.getIntPtrType(AddrModes[0].OriginalValue->getType());
     for (auto &AM : AddrModes) {
       Value *DV = AM.GetFieldAsValue(DifferentField, IntPtrTy);
       if (DV) {
@@ -4306,7 +4278,7 @@ class AddressingModeCombiner {
     // simplification is possible only if original phi/selects were not
     // simplified yet.
     // Using this mapping we can find the current value in AddrToBase.
-    SimplificationTracker ST(SQ);
+    SimplificationTracker ST;
 
     // First step, DFS to create PHI nodes for all intermediate blocks.
     // Also fill traverse order for the second step.
@@ -4465,7 +4437,6 @@ class AddressingModeCombiner {
           PHI->addIncoming(ST.Get(Map[PV]), B);
         }
       }
-      Map[Current] = ST.Simplify(V);
     }
   }
 
@@ -5856,8 +5827,7 @@ bool CodeGenPrepare::optimizeMemoryInst(Instruction *MemoryInst, Value *Addr,
   // the graph are compatible.
   bool PhiOrSelectSeen = false;
   SmallVector<Instruction *, 16> AddrModeInsts;
-  const SimplifyQuery SQ(*DL, TLInfo);
-  AddressingModeCombiner AddrModes(SQ, Addr);
+  AddressingModeCombiner AddrModes(*DL, Addr);
   TypePromotionTransaction TPT(RemovedInsts);
   TypePromotionTransaction::ConstRestorationPt LastKnownGood =
       TPT.getRestorationPoint();

llvm/test/Transforms/CodeGenPrepare/X86/sink-addrmode-base.ll

@@ -951,3 +951,41 @@ fallthrough:
   %v = add i32 %v1, %v2
   ret i32 %v
 }
+
+; Make sure we don't simplify an incomplete expression tree.
+define i8 @pr163453(ptr %p, i1 %cond) {
+; CHECK-LABEL: define i8 @pr163453(
+; CHECK-SAME: ptr [[P:%.*]], i1 [[COND:%.*]]) {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[P_ADDR_0:%.*]] = getelementptr i8, ptr [[P]], i64 1
+; CHECK-NEXT:    [[TMP0:%.*]] = load i8, ptr [[P]], align 1
+; CHECK-NEXT:    [[INCDEC_PTR11:%.*]] = getelementptr i8, ptr [[P]], i64 2
+; CHECK-NEXT:    [[SPEC_SELECT:%.*]] = select i1 [[COND]], ptr [[P_ADDR_0]], ptr [[INCDEC_PTR11]]
+; CHECK-NEXT:    [[LOAD:%.*]] = load i8, ptr [[SPEC_SELECT]], align 1
+; CHECK-NEXT:    ret i8 [[LOAD]]
+;
+entry:
+  br label %for.cond
+
+for.cond:
+  %p.pn = phi ptr [ %p, %entry ], [ %p.addr.0, %for.inc ]
+  %p.addr.0 = getelementptr i8, ptr %p.pn, i64 1
+  br i1 false, label %exit, label %for.body
+
+for.body:
+  %1 = load i8, ptr %p.pn, align 1
+  br i1 false, label %for.inc, label %if.else
+
+if.else:
+  %incdec.ptr11 = getelementptr i8, ptr %p.pn, i64 2
+  %spec.select = select i1 %cond, ptr %p.addr.0, ptr %incdec.ptr11
+  br label %exit
+
+for.inc:
+  br label %for.cond
+
+exit:
+  %p.addr.3 = phi ptr [ %spec.select, %if.else ], [ %p.addr.0, %for.cond ]
+  %load = load i8, ptr %p.addr.3, align 1
+  ret i8 %load
+}