Automerge: [LegalizeTypes] Preserve disjoint flag when expanding OR. (#147640)

Author: topperc

llvm/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp

@@ -4380,8 +4380,13 @@ void DAGTypeLegalizer::ExpandIntRes_Logical(SDNode *N,
   SDValue LL, LH, RL, RH;
   GetExpandedInteger(N->getOperand(0), LL, LH);
   GetExpandedInteger(N->getOperand(1), RL, RH);
-  Lo = DAG.getNode(N->getOpcode(), dl, LL.getValueType(), LL, RL);
-  Hi = DAG.getNode(N->getOpcode(), dl, LL.getValueType(), LH, RH);
+
+  SDNodeFlags Flags;
+  if (N->getOpcode() == ISD::OR)
+    Flags.setDisjoint(N->getFlags().hasDisjoint());
+
+  Lo = DAG.getNode(N->getOpcode(), dl, LL.getValueType(), LL, RL, Flags);
+  Hi = DAG.getNode(N->getOpcode(), dl, LL.getValueType(), LH, RH, Flags);
 }
 
 void DAGTypeLegalizer::ExpandIntRes_MUL(SDNode *N,

llvm/test/CodeGen/RISCV/rv32zbb-zbkb.ll

@@ -128,13 +128,19 @@ define i32 @disjoint_or_xnor_i32(i32 %a, i32 %b) nounwind {
 }
 
 define i64 @disjoint_or_xnor_i64(i64 %a, i64 %b) nounwind {
-; CHECK-LABEL: disjoint_or_xnor_i64:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    or a1, a1, a3
-; CHECK-NEXT:    or a0, a0, a2
-; CHECK-NEXT:    not a0, a0
-; CHECK-NEXT:    not a1, a1
-; CHECK-NEXT:    ret
+; RV32I-LABEL: disjoint_or_xnor_i64:
+; RV32I:       # %bb.0:
+; RV32I-NEXT:    or a1, a1, a3
+; RV32I-NEXT:    or a0, a0, a2
+; RV32I-NEXT:    not a0, a0
+; RV32I-NEXT:    not a1, a1
+; RV32I-NEXT:    ret
+;
+; RV32ZBB-ZBKB-LABEL: disjoint_or_xnor_i64:
+; RV32ZBB-ZBKB:       # %bb.0:
+; RV32ZBB-ZBKB-NEXT:    xnor a0, a0, a2
+; RV32ZBB-ZBKB-NEXT:    xnor a1, a1, a3
+; RV32ZBB-ZBKB-NEXT:    ret
   %or = or disjoint i64 %a, %b
   %not = xor i64 %or, -1
   ret i64 %not