Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -18590,6 +18590,24 @@
     }
   }
 
+  // (ctpop x) == 1 --> (x != 0) && ((x & x-1) == 0)
+  // (ctpop x) != 1 --> (x == 0) || ((x & x-1) != 0)
+  if (LHS.getOpcode() == ISD::CTPOP && LHS.hasOneUse() && isOneConstant(RHS) &&
+      (Cond == ISD::SETEQ || Cond == ISD::SETNE)) {
+    EVT CTVT = LHS.getValueType();
+    SDValue X = LHS.getOperand(0);
+    SDValue Zero = DAG.getConstant(0, DL, CTVT);
+    SDValue NegOne = DAG.getAllOnesConstant(DL, CTVT);
+    assert(CTVT.isInteger());
+    ISD::CondCode InvCond = ISD::getSetCCInverse(Cond, CTVT);
+    SDValue Add = DAG.getNode(ISD::ADD, DL, CTVT, X, NegOne);
+    SDValue And = DAG.getNode(ISD::AND, DL, CTVT, X, Add);
+    SDValue LHS = DAG.getSetCC(DL, VT, X, Zero, InvCond);
+    SDValue RHS = DAG.getSetCC(DL, VT, And, Zero, Cond);
+    unsigned LogicOpcode = Cond == ISD::SETEQ ? ISD::AND : ISD::OR;
+    return DAG.getNode(LogicOpcode, DL, VT, LHS, RHS);
+  }
+
   return SDValue();
 }
 
Index: llvm/test/CodeGen/AArch64/arm64-popcnt.ll
===================================================================
--- llvm/test/CodeGen/AArch64/arm64-popcnt.ll
+++ llvm/test/CodeGen/AArch64/arm64-popcnt.ll
@@ -168,30 +168,18 @@
 define i32 @ctpop_eq_one(i64 %x) nounwind readnone {
 ; CHECK-LABEL: ctpop_eq_one:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    fmov d0, x0
-; CHECK-NEXT:    cnt.8b v0, v0
-; CHECK-NEXT:    uaddlv.8b h0, v0
-; CHECK-NEXT:    fmov w8, s0
-; CHECK-NEXT:    cmp x8, #1
-; CHECK-NEXT:    cset w0, eq
+; CHECK-NEXT:    sub x8, x0, #1
+; CHECK-NEXT:    tst x0, x8
+; CHECK-NEXT:    ccmp x0, #0, #4, eq
+; CHECK-NEXT:    cset w0, ne
 ; CHECK-NEXT:    ret
 ;
 ; CHECK-NONEON-LABEL: ctpop_eq_one:
 ; CHECK-NONEON:       // %bb.0:
-; CHECK-NONEON-NEXT:    lsr x9, x0, #1
-; CHECK-NONEON-NEXT:    mov x8, #72340172838076673
-; CHECK-NONEON-NEXT:    and x9, x9, #0x5555555555555555
-; CHECK-NONEON-NEXT:    sub x9, x0, x9
-; CHECK-NONEON-NEXT:    lsr x10, x9, #2
-; CHECK-NONEON-NEXT:    and x9, x9, #0x3333333333333333
-; CHECK-NONEON-NEXT:    and x10, x10, #0x3333333333333333
-; CHECK-NONEON-NEXT:    add x9, x9, x10
-; CHECK-NONEON-NEXT:    add x9, x9, x9, lsr #4
-; CHECK-NONEON-NEXT:    and x9, x9, #0xf0f0f0f0f0f0f0f
-; CHECK-NONEON-NEXT:    mul x8, x9, x8
-; CHECK-NONEON-NEXT:    lsr x8, x8, #56
-; CHECK-NONEON-NEXT:    cmp x8, #1
-; CHECK-NONEON-NEXT:    cset w0, eq
+; CHECK-NONEON-NEXT:    sub x8, x0, #1
+; CHECK-NONEON-NEXT:    tst x0, x8
+; CHECK-NONEON-NEXT:    ccmp x0, #0, #4, eq
+; CHECK-NONEON-NEXT:    cset w0, ne
 ; CHECK-NONEON-NEXT:    ret
   %count = tail call i64 @llvm.ctpop.i64(i64 %x)
   %cmp = icmp eq i64 %count, 1
@@ -202,30 +190,18 @@
 define i32 @ctpop_ne_one(i64 %x) nounwind readnone {
 ; CHECK-LABEL: ctpop_ne_one:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    fmov d0, x0
-; CHECK-NEXT:    cnt.8b v0, v0
-; CHECK-NEXT:    uaddlv.8b h0, v0
-; CHECK-NEXT:    fmov w8, s0
-; CHECK-NEXT:    cmp x8, #1
-; CHECK-NEXT:    cset w0, ne
+; CHECK-NEXT:    sub x8, x0, #1
+; CHECK-NEXT:    tst x0, x8
+; CHECK-NEXT:    ccmp x0, #0, #4, eq
+; CHECK-NEXT:    cset w0, eq
 ; CHECK-NEXT:    ret
 ;
 ; CHECK-NONEON-LABEL: ctpop_ne_one:
 ; CHECK-NONEON:       // %bb.0:
-; CHECK-NONEON-NEXT:    lsr x9, x0, #1
-; CHECK-NONEON-NEXT:    mov x8, #72340172838076673
-; CHECK-NONEON-NEXT:    and x9, x9, #0x5555555555555555
-; CHECK-NONEON-NEXT:    sub x9, x0, x9
-; CHECK-NONEON-NEXT:    lsr x10, x9, #2
-; CHECK-NONEON-NEXT:    and x9, x9, #0x3333333333333333
-; CHECK-NONEON-NEXT:    and x10, x10, #0x3333333333333333
-; CHECK-NONEON-NEXT:    add x9, x9, x10
-; CHECK-NONEON-NEXT:    add x9, x9, x9, lsr #4
-; CHECK-NONEON-NEXT:    and x9, x9, #0xf0f0f0f0f0f0f0f
-; CHECK-NONEON-NEXT:    mul x8, x9, x8
-; CHECK-NONEON-NEXT:    lsr x8, x8, #56
-; CHECK-NONEON-NEXT:    cmp x8, #1
-; CHECK-NONEON-NEXT:    cset w0, ne
+; CHECK-NONEON-NEXT:    sub x8, x0, #1
+; CHECK-NONEON-NEXT:    tst x0, x8
+; CHECK-NONEON-NEXT:    ccmp x0, #0, #4, eq
+; CHECK-NONEON-NEXT:    cset w0, eq
 ; CHECK-NONEON-NEXT:    ret
   %count = tail call i64 @llvm.ctpop.i64(i64 %x)
   %cmp = icmp ne i64 %count, 1