Index: llvm/docs/LangRef.rst
===================================================================
--- llvm/docs/LangRef.rst
+++ llvm/docs/LangRef.rst
@@ -16443,6 +16443,42 @@
 On the other hand, if constant folding is not run, it will never
 evaluate to true, even in simple cases.
 
+.. _int_ptrmask:
+
+'``llvm.ptrmask``' Intrinsic
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+::
+
+      declare ptrty llvm.ptrmask(ptrty %ptr, intty %mask) readnone
+
+Arguments:
+""""""""""
+
+The first argument is a pointer. The second argument is an integer.
+
+Overview:
+""""""""""
+
+The ``llvm.ptrmask`` intrinsic masks out bits of the pointer according to a mask.
+This allows stripping data from tagged pointers without converting them to an
+integer (ptrtoint/inttoptr). As a consequence, we can preserve more information
+to facilitate alias analysis and underlying object detection.
+
+Semantics:
+""""""""""
+
+The effect of this intrinsic is to ensure that
+``ptrtoint(ptrmask(ptr, mask)) == (ptrtoint(ptr) & mask)``. Both the returned
+pointer and the first argument are based on the same underlying object (for more
+information on the *based* on terminology see
+:ref:`the pointer aliasing rules <pointeraliasing>`). If the bitwidth of the
+mask argument does not match the pointer size of the target, the mask is
+zero-extended or truncated accordingly.
+
 Stack Map Intrinsics
 --------------------
 
Index: llvm/include/llvm/IR/Intrinsics.td
===================================================================
--- llvm/include/llvm/IR/Intrinsics.td
+++ llvm/include/llvm/IR/Intrinsics.td
@@ -1028,6 +1028,9 @@
 // Intrinsic to detect whether its argument is a constant.
 def int_is_constant : Intrinsic<[llvm_i1_ty], [llvm_any_ty], [IntrNoMem], "llvm.is.constant">;
 
+// Intrinsic to mask out bits of a pointer.
+def int_ptrmask: Intrinsic<[llvm_anyptr_ty], [llvm_anyptr_ty, llvm_anyint_ty],
+                           [IntrNoMem, IntrSpeculatable]>;
 
 //===-------------------------- Masked Intrinsics -------------------------===//
 //
Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6809,6 +6809,17 @@
     // MachineFunction in SelectionDAGISel::PrepareEHLandingPad. We can safely
     // delete it now.
     return nullptr;
+  case Intrinsic::ptrmask: {
+    SDValue Ptr = getValue(I.getOperand(0));
+    SDValue Const = getValue(I.getOperand(1));
+
+    EVT DestVT =
+        EVT(DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout()));
+
+    setValue(&I, DAG.getNode(ISD::AND, getCurSDLoc(), DestVT, Ptr,
+                             DAG.getZExtOrTrunc(Const, getCurSDLoc(), DestVT)));
+    return nullptr;
+  }
   }
 }
 
Index: llvm/test/CodeGen/AArch64/lower-ptrmask.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/AArch64/lower-ptrmask.ll
@@ -0,0 +1,29 @@
+; RUN: llc -mtriple=arm64-apple-iphoneos -stop-after=expand-isel-pseudos %s -o - | FileCheck %s
+
+declare i8* @llvm.ptrmask.p0i8.i64(i8* , i64)
+
+; CHECK-LABEL: name: test1
+; CHECK:         %0:gpr64 = COPY $x0
+; CHECK-NEXT:    %1:gpr64sp = ANDXri %0, 8052
+; CHECK-NEXT:    $x0 = COPY %1
+; CHECK-NEXT:    RET_ReallyLR implicit $x0
+
+define i8* @test1(i8* %src) {
+  %ptr = call i8* @llvm.ptrmask.p0i8.i64(i8* %src, i64 72057594037927928)
+  ret i8* %ptr
+}
+
+declare i8* @llvm.ptrmask.p0i8.i32(i8*, i32)
+
+; CHECK-LABEL: name: test2
+; CHECK:         %0:gpr64 = COPY $x0
+; CHECK-NEXT:    %1:gpr32 = MOVi32imm 10000
+; CHECK-NEXT:    %2:gpr64 = SUBREG_TO_REG 0, killed %1, %subreg.sub_32
+; CHECK-NEXT:    %3:gpr64 = ANDXrr %0, killed %2
+; CHECK-NEXT:    $x0 = COPY %3
+; CHECK-NEXT:    RET_ReallyLR implicit $x0
+
+define i8* @test2(i8* %src) {
+  %ptr = call i8* @llvm.ptrmask.p0i8.i32(i8* %src, i32 10000)
+  ret i8* %ptr
+}
Index: llvm/test/CodeGen/X86/lower-ptrmask.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/lower-ptrmask.ll
@@ -0,0 +1,31 @@
+; RUN: llc -mtriple=x86_64-apple-macosx -stop-after=expand-isel-pseudos %s -o - | FileCheck %s
+
+declare i8* @llvm.ptrmask.p0i8.i64(i8* , i64)
+
+; CHECK-LABEL: name: test1
+; CHECK:         %0:gr64 = COPY $rdi
+; CHECK-NEXT:    %1:gr64 = MOV64ri 72057594037927928
+; CHECK-NEXT:    %2:gr64 = AND64rr %0, killed %1, implicit-def dead $eflags
+; CHECK-NEXT:    $rax = COPY %2
+; CHECK-NEXT:    RET 0, $rax
+
+define i8* @test1(i8* %src) {
+  %ptr = call i8* @llvm.ptrmask.p0i8.i64(i8* %src, i64 72057594037927928)
+  ret i8* %ptr
+}
+
+declare i8* @llvm.ptrmask.p0i8.i32(i8*, i32)
+
+; CHECK-LABEL: name: test2
+; CHECK:         %0:gr64 = COPY $rdi
+; CHECK-NEXT:    %1:gr32 = COPY %0.sub_32bit
+; CHECK-NEXT:    %2:gr32 = AND32ri %1, 10000, implicit-def dead $eflags
+; CHECK-NEXT:    %3:gr64 = SUBREG_TO_REG 0, killed %2, %subreg.sub_32bit
+; CHECK-NEXT:    $rax = COPY %3
+; CHECK-NEXT:    RET 0, $rax
+
+
+define i8* @test2(i8* %src) {
+  %ptr = call i8* @llvm.ptrmask.p0i8.i32(i8* %src, i32 10000)
+  ret i8* %ptr
+}