[GVN][NewGVN] Take call attributes into account in expressions (llvm#114545)

Drop `canBeReplacedBy` and take call attributes into account in
expressions.
Address comment
llvm#114011 (review).

Author: dtcxzyw

llvm/include/llvm/Transforms/Scalar/GVNExpression.h

@@ -315,6 +315,12 @@ class CallExpression final : public MemoryExpression {
     return EB->getExpressionType() == ET_Call;
   }
 
+  bool equals(const Expression &Other) const override;
+  bool exactlyEquals(const Expression &Other) const override {
+    return Expression::exactlyEquals(Other) &&
+           cast<CallExpression>(Other).Call == Call;
+  }
+
   // Debugging support
   void printInternal(raw_ostream &OS, bool PrintEType) const override {
     if (PrintEType)

llvm/lib/Transforms/Scalar/GVN.cpp

@@ -143,6 +143,8 @@ struct llvm::GVNPass::Expression {
   Type *type = nullptr;
   SmallVector<uint32_t, 4> varargs;
 
+  AttributeList attrs;
+
   Expression(uint32_t o = ~2U) : opcode(o) {}
 
   bool operator==(const Expression &other) const {
@@ -154,6 +156,9 @@ struct llvm::GVNPass::Expression {
       return false;
     if (varargs != other.varargs)
       return false;
+    if (!attrs.isEmpty() && !other.attrs.isEmpty() &&
+        !attrs.intersectWith(type->getContext(), other.attrs).has_value())
+      return false;
     return true;
   }
 
@@ -364,6 +369,8 @@ GVNPass::Expression GVNPass::ValueTable::createExpr(Instruction *I) {
   } else if (auto *SVI = dyn_cast<ShuffleVectorInst>(I)) {
     ArrayRef<int> ShuffleMask = SVI->getShuffleMask();
     e.varargs.append(ShuffleMask.begin(), ShuffleMask.end());
+  } else if (auto *CB = dyn_cast<CallBase>(I)) {
+    e.attrs = CB->getAttributes();
   }
 
   return e;
@@ -2136,16 +2143,6 @@ bool GVNPass::processAssumeIntrinsic(AssumeInst *IntrinsicI) {
   return Changed;
 }
 
-// Return true iff V1 can be replaced with V2.
-static bool canBeReplacedBy(Value *V1, Value *V2) {
-  if (auto *CB1 = dyn_cast<CallBase>(V1))
-    if (auto *CB2 = dyn_cast<CallBase>(V2))
-      return CB1->getAttributes()
-          .intersectWith(CB2->getContext(), CB2->getAttributes())
-          .has_value();
-  return true;
-}
-
 static void patchAndReplaceAllUsesWith(Instruction *I, Value *Repl) {
   patchReplacementInstruction(I, Repl);
   I->replaceAllUsesWith(Repl);
@@ -2690,7 +2687,7 @@ bool GVNPass::processInstruction(Instruction *I) {
   // Perform fast-path value-number based elimination of values inherited from
   // dominators.
   Value *Repl = findLeader(I->getParent(), Num);
-  if (!Repl || !canBeReplacedBy(I, Repl)) {
+  if (!Repl) {
     // Failure, just remember this instance for future use.
     LeaderTable.insert(Num, I, I->getParent());
     return false;
@@ -2956,7 +2953,7 @@ bool GVNPass::performScalarPRE(Instruction *CurInst) {
 
     uint32_t TValNo = VN.phiTranslate(P, CurrentBlock, ValNo, *this);
     Value *predV = findLeader(P, TValNo);
-    if (!predV || !canBeReplacedBy(CurInst, predV)) {
+    if (!predV) {
       predMap.push_back(std::make_pair(static_cast<Value *>(nullptr), P));
       PREPred = P;
       ++NumWithout;

llvm/lib/Transforms/Scalar/NewGVN.cpp

@@ -945,6 +945,18 @@ bool StoreExpression::equals(const Expression &Other) const {
   return true;
 }
 
+bool CallExpression::equals(const Expression &Other) const {
+  if (!MemoryExpression::equals(Other))
+    return false;
+
+  if (auto *RHS = dyn_cast<CallExpression>(&Other))
+    return Call->getAttributes()
+        .intersectWith(Call->getContext(), RHS->Call->getAttributes())
+        .has_value();
+
+  return false;
+}
+
 // Determine if the edge From->To is a backedge
 bool NewGVN::isBackedge(BasicBlock *From, BasicBlock *To) const {
   return From == To ||
@@ -3854,16 +3866,6 @@ Value *NewGVN::findPHIOfOpsLeader(const Expression *E,
   return nullptr;
 }
 
-// Return true iff V1 can be replaced with V2.
-static bool canBeReplacedBy(Value *V1, Value *V2) {
-  if (auto *CB1 = dyn_cast<CallBase>(V1))
-    if (auto *CB2 = dyn_cast<CallBase>(V2))
-      return CB1->getAttributes()
-          .intersectWith(CB2->getContext(), CB2->getAttributes())
-          .has_value();
-  return true;
-}
-
 bool NewGVN::eliminateInstructions(Function &F) {
   // This is a non-standard eliminator. The normal way to eliminate is
   // to walk the dominator tree in order, keeping track of available
@@ -3973,8 +3975,6 @@ bool NewGVN::eliminateInstructions(Function &F) {
           MembersLeft.insert(Member);
           continue;
         }
-        if (!canBeReplacedBy(Member, Leader))
-          continue;
 
         LLVM_DEBUG(dbgs() << "Found replacement " << *(Leader) << " for "
                           << *Member << "\n");
@@ -4082,11 +4082,8 @@ bool NewGVN::eliminateInstructions(Function &F) {
               if (DominatingLeader != Def) {
                 // Even if the instruction is removed, we still need to update
                 // flags/metadata due to downstreams users of the leader.
-                if (!match(DefI, m_Intrinsic<Intrinsic::ssa_copy>())) {
-                  if (!canBeReplacedBy(DefI, DominatingLeader))
-                    continue;
+                if (!match(DefI, m_Intrinsic<Intrinsic::ssa_copy>()))
                   patchReplacementInstruction(DefI, DominatingLeader);
-                }
 
                 markInstructionForDeletion(DefI);
               }
@@ -4134,11 +4131,8 @@ bool NewGVN::eliminateInstructions(Function &F) {
           // original operand, as we already know we can just drop it.
           auto *ReplacedInst = cast<Instruction>(U->get());
           auto *PI = PredInfo->getPredicateInfoFor(ReplacedInst);
-          if (!PI || DominatingLeader != PI->OriginalOp) {
-            if (!canBeReplacedBy(ReplacedInst, DominatingLeader))
-              continue;
+          if (!PI || DominatingLeader != PI->OriginalOp)
             patchReplacementInstruction(ReplacedInst, DominatingLeader);
-          }
 
           LLVM_DEBUG(dbgs()
                      << "Found replacement " << *DominatingLeader << " for "

llvm/test/Transforms/GVN/pr113997.ll

@@ -31,3 +31,39 @@ if.else:
 if.then:
   ret i1 false
 }
+
+; Make sure we don't merge these two users of the incompatible call pair.
+
+define i1 @bucket2(i32 noundef %x) {
+; CHECK-LABEL: define i1 @bucket2(
+; CHECK-SAME: i32 noundef [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[X]], 0
+; CHECK-NEXT:    [[CTPOP1:%.*]] = tail call range(i32 1, 32) i32 @llvm.ctpop.i32(i32 zeroext [[X]])
+; CHECK-NEXT:    [[CTPOP1INC:%.*]] = add i32 [[CTPOP1]], 1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp samesign ult i32 [[CTPOP1INC]], 3
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[CMP1]], i1 [[CMP2]], i1 false
+; CHECK-NEXT:    br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
+; CHECK:       [[IF_ELSE]]:
+; CHECK-NEXT:    [[CTPOP2:%.*]] = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[X]])
+; CHECK-NEXT:    [[CTPOP2INC:%.*]] = add i32 [[CTPOP2]], 1
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i32 [[CTPOP2INC]], 2
+; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK:       [[IF_THEN]]:
+; CHECK-NEXT:    ret i1 false
+;
+  %cmp1 = icmp sgt i32 %x, 0
+  %ctpop1 = tail call range(i32 1, 32) i32 @llvm.ctpop.i32(i32 zeroext %x)
+  %ctpop1inc = add i32 %ctpop1, 1
+  %cmp2 = icmp samesign ult i32 %ctpop1inc, 3
+  %cond = select i1 %cmp1, i1 %cmp2, i1 false
+  br i1 %cond, label %if.then, label %if.else
+
+if.else:
+  %ctpop2 = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 %x)
+  %ctpop2inc = add i32 %ctpop2, 1
+  %res = icmp eq i32 %ctpop2inc, 2
+  ret i1 %res
+
+if.then:
+  ret i1 false
+}

llvm/test/Transforms/NewGVN/pr113997.ll

@@ -31,3 +31,39 @@ if.else:
 if.then:
   ret i1 false
 }
+
+; Make sure we don't merge these two users of the incompatible call pair.
+
+define i1 @bucket2(i32 noundef %x) {
+; CHECK-LABEL: define i1 @bucket2(
+; CHECK-SAME: i32 noundef [[X:%.*]]) {
+; CHECK-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[X]], 0
+; CHECK-NEXT:    [[CTPOP1:%.*]] = tail call range(i32 1, 32) i32 @llvm.ctpop.i32(i32 zeroext [[X]])
+; CHECK-NEXT:    [[CTPOP1INC:%.*]] = add i32 [[CTPOP1]], 1
+; CHECK-NEXT:    [[CMP2:%.*]] = icmp samesign ult i32 [[CTPOP1INC]], 3
+; CHECK-NEXT:    [[COND:%.*]] = select i1 [[CMP1]], i1 [[CMP2]], i1 false
+; CHECK-NEXT:    br i1 [[COND]], label %[[IF_THEN:.*]], label %[[IF_ELSE:.*]]
+; CHECK:       [[IF_ELSE]]:
+; CHECK-NEXT:    [[CTPOP2:%.*]] = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 [[X]])
+; CHECK-NEXT:    [[CTPOP2INC:%.*]] = add i32 [[CTPOP2]], 1
+; CHECK-NEXT:    [[RES:%.*]] = icmp eq i32 [[CTPOP2INC]], 2
+; CHECK-NEXT:    ret i1 [[RES]]
+; CHECK:       [[IF_THEN]]:
+; CHECK-NEXT:    ret i1 false
+;
+  %cmp1 = icmp sgt i32 %x, 0
+  %ctpop1 = tail call range(i32 1, 32) i32 @llvm.ctpop.i32(i32 zeroext %x)
+  %ctpop1inc = add i32 %ctpop1, 1
+  %cmp2 = icmp samesign ult i32 %ctpop1inc, 3
+  %cond = select i1 %cmp1, i1 %cmp2, i1 false
+  br i1 %cond, label %if.then, label %if.else
+
+if.else:
+  %ctpop2 = tail call range(i32 0, 33) i32 @llvm.ctpop.i32(i32 %x)
+  %ctpop2inc = add i32 %ctpop2, 1
+  %res = icmp eq i32 %ctpop2inc, 2
+  ret i1 %res
+
+if.then:
+  ret i1 false
+}