diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -4201,7 +4201,7 @@
 }
 
 static bool areOperandsOfHigherHalf(SDValue &Op1, SDValue &Op2) {
-  return isOperandOfHigherHalf(Op1) && isOperandOfHigherHalf(Op2);
+  return isOperandOfHigherHalf(Op1) || isOperandOfHigherHalf(Op2);
 }
 
 static bool isExtendedBUILD_VECTOR(SDNode *N, SelectionDAG &DAG,
@@ -4548,7 +4548,7 @@
     SDValue Op1 = Op.getOperand(1);
     SDValue Op2 = Op.getOperand(2);
 
-    // If both operands are higher half of two source SIMD & FP registers,
+    // If either operand is the higher half of two source SIMD & FP registers,
     // ISel could make use of tablegen patterns to emit PMULL2. So do not
     // legalize i64 to v1i64.
     if (areOperandsOfHigherHalf(Op1, Op2))
diff --git a/llvm/lib/Target/AArch64/AArch64InstrInfo.td b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
--- a/llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ b/llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -5546,6 +5546,11 @@
 def DUPv8i8lane  : SIMDDup8FromElement <0, ".8b", v8i8, V64>;
 def DUPv16i8lane : SIMDDup8FromElement <1, ".16b", v16i8, V128>;
 
+// FIXME: We may want to canonicalize to put V64 argument as the second argument.
+def : Pat<(int_aarch64_neon_pmull64 (extractelt (v2i64 V128:$Rn), (i64 1)),
+                                    V64:$Rm),
+          (PMULLv2i64 V128:$Rn, (v2f64 (DUPv2i64lane (INSERT_SUBREG (v2i64 (IMPLICIT_DEF)), V64:$Rm, dsub), (i64 0))))>;
+
 // DUP from a 64-bit register to a 64-bit register is just a copy
 def : Pat<(v1i64 (AArch64dup (i64 GPR64:$Rn))),
           (COPY_TO_REGCLASS GPR64:$Rn, FPR64)>;
diff --git a/llvm/test/CodeGen/AArch64/pmull-ldr-merge.ll b/llvm/test/CodeGen/AArch64/pmull-ldr-merge.ll
--- a/llvm/test/CodeGen/AArch64/pmull-ldr-merge.ll
+++ b/llvm/test/CodeGen/AArch64/pmull-ldr-merge.ll
@@ -1,5 +1,5 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc -verify-machineinstrs  -mtriple=aarch64-linux-gnu -mattr=+aes -o - %s| FileCheck %s --check-prefixes=CHECK
+; RUN: llc -O3 -verify-machineinstrs  -mtriple=aarch64-linux-gnu -mattr=+aes -o - %s| FileCheck %s --check-prefixes=CHECK
 
 ; Tests that scalar i64 arguments of llvm.aarch64.neon.pmull64 are
 ; loaded into SIMD registers, as opposed to being loaded into GPR followed by a mov.
@@ -27,18 +27,18 @@
 define void @test2(ptr %0, i64 %1, i64 %2, <2 x i64> %3) {
 ; CHECK-LABEL: test2:
 ; CHECK:       // %bb.0:
-; CHECK-NEXT:    mov x9, v0.d[1]
 ; CHECK-NEXT:    add x8, x0, x1, lsl #4
-; CHECK-NEXT:    ldr d0, [x8, #8]
+; CHECK-NEXT:    ldr x9, [x8, #8]
 ; CHECK-NEXT:    fmov d1, x9
-; CHECK-NEXT:    pmull v0.1q, v0.1d, v1.1d
+; CHECK-NEXT:    dup v1.2d, v1.d[0]
+; CHECK-NEXT:    pmull2 v0.1q, v0.2d, v1.2d
 ; CHECK-NEXT:    str q0, [x8]
 ; CHECK-NEXT:    ret
   %5 = getelementptr inbounds <2 x i64>, ptr %0, i64 %1
   %6 = getelementptr inbounds <2 x i64>, ptr %0, i64 %1, i64 1
   %7 = load i64, ptr %6, align 8
   %8 = extractelement <2 x i64> %3, i64 1
-  %9 = tail call <16 x i8> @llvm.aarch64.neon.pmull64(i64 %7, i64 %8)
+  %9 = tail call <16 x i8> @llvm.aarch64.neon.pmull64(i64 %8, i64 %7)
   store <16 x i8> %9, ptr %5, align 16
   ret void
 }
@@ -60,4 +60,51 @@
   ret void
 }
 
+define void @test4(ptr %0, ptr %1) {
+; CHECK-LABEL: func:
+; CHECK:       // %bb.0:
+; CHECK-NEXT:    mov w8, #56824
+; CHECK-NEXT:    mov w9, #61186
+; CHECK-NEXT:    movk w8, #40522, lsl #16
+; CHECK-NEXT:    movk w9, #29710, lsl #16
+; CHECK-NEXT:    ldp q2, q3, [x1]
+; CHECK-NEXT:    fmov d0, x8
+; CHECK-NEXT:    fmov d1, x9
+; CHECK-NEXT:    dup v0.2d, v0.d[0]
+; CHECK-NEXT:    pmull v4.1q, v2.1d, v1.1d
+; CHECK-NEXT:    pmull v1.1q, v3.1d, v1.1d
+; CHECK-NEXT:    pmull2 v2.1q, v2.2d, v0.2d
+; CHECK-NEXT:    pmull2 v0.1q, v3.2d, v0.2d
+; CHECK-NEXT:    ldp q3, q5, [x0]
+; CHECK-NEXT:    eor v2.16b, v4.16b, v2.16b
+; CHECK-NEXT:    eor v0.16b, v1.16b, v0.16b
+; CHECK-NEXT:    eor v1.16b, v3.16b, v2.16b
+; CHECK-NEXT:    eor v0.16b, v5.16b, v0.16b
+; CHECK-NEXT:    stp q1, q0, [x1]
+; CHECK-NEXT:    ret
+  %3 = load <2 x i64>, ptr %1
+  %4 = getelementptr inbounds <2 x i64>, ptr %1, i64 1
+  %5 = load <2 x i64>, ptr %4
+  %6 = extractelement <2 x i64> %3, i64 1
+  %7 = tail call <16 x i8> @llvm.aarch64.neon.pmull64(i64 %6, i64 2655706616)
+  %8 = extractelement <2 x i64> %5, i64 1
+  %9 = tail call <16 x i8> @llvm.aarch64.neon.pmull64(i64 %8, i64 2655706616)
+  %10 = load <2 x i64>, ptr %0
+  %11 = getelementptr inbounds i8, ptr %0, i64 16
+  %12 = load <2 x i64>, ptr %11
+  %13 = extractelement <2 x i64> %3, i64 0
+  %14 = tail call <16 x i8> @llvm.aarch64.neon.pmull64(i64 %13, i64 1947135746)
+  %15 = extractelement <2 x i64> %5, i64 0
+  %16 = tail call <16 x i8> @llvm.aarch64.neon.pmull64(i64 %15, i64 1947135746)
+  %17 = xor <16 x i8> %14, %7
+  %18 = bitcast <16 x i8> %17 to <2 x i64>
+  %19 = xor <16 x i8> %16, %9
+  %20 = bitcast <16 x i8> %19 to <2 x i64>
+  %21 = xor <2 x i64> %10, %18
+  %22 = xor <2 x i64> %12, %20
+  store <2 x i64> %21, ptr %1
+  store <2 x i64> %22, ptr %4
+  ret void
+}
+
 declare <16 x i8> @llvm.aarch64.neon.pmull64(i64, i64)