Index: llvm/lib/Analysis/TypeMetadataUtils.cpp
===================================================================
--- llvm/lib/Analysis/TypeMetadataUtils.cpp
+++ llvm/lib/Analysis/TypeMetadataUtils.cpp
@@ -155,5 +155,20 @@
     return getPointerAtOffset(cast<Constant>(I->getOperand(Op)),
                               Offset % ElemSize, M);
   }
+  if (auto *CI = dyn_cast<ConstantInt>(I)) {
+    if (Offset == 0 && CI->getZExtValue() == 0) {
+      return I;
+    }
+  }
+  if (auto *C = dyn_cast<ConstantExpr>(I)) {
+    switch (C->getOpcode()) {
+      case Instruction::Trunc:
+      case Instruction::PtrToInt:
+      case Instruction::Sub:
+        return getPointerAtOffset(cast<Constant>(C->getOperand(0)), Offset, M);
+      default:
+        return nullptr;
+    }
+  }
   return nullptr;
 }
Index: llvm/lib/Transforms/IPO/GlobalDCE.cpp
===================================================================
--- llvm/lib/Transforms/IPO/GlobalDCE.cpp
+++ llvm/lib/Transforms/IPO/GlobalDCE.cpp
@@ -131,11 +131,38 @@
     // complete information about all virtual call sites which could call
     // though this vtable, then skip it, because the call site information will
     // be more precise.
+    bool IgnoreDependency = false;
+
     if (VFESafeVTables.count(GVU) && isa<Function>(&GV)) {
+      // Scan the !type metadata on the vtable and also ignore those deps that
+      // have an offset in one of the !type entries.
+      if (auto VTable = dyn_cast<GlobalVariable>(GVU)) {
+        SmallVector<MDNode *, 2> Types;
+        VTable->getMetadata(LLVMContext::MD_type, Types);
+        if (!VTable->isDeclaration() && !Types.empty()) {
+          for (MDNode *Type : Types) {
+            uint64_t OffsetInType =
+                cast<ConstantInt>(
+                    cast<ConstantAsMetadata>(Type->getOperand(0))->getValue())
+                    ->getZExtValue();
+            Constant *Ptr = getPointerAtOffset(
+                VTable->getInitializer(), OffsetInType, *VTable->getParent());
+            Ptr = Ptr ? Ptr->stripPointerCasts() : nullptr;
+            if (Ptr == &GV) {
+              IgnoreDependency = true;
+              break;
+            }
+          }
+        }
+      }
+    }
+
+    if (IgnoreDependency) {
       LLVM_DEBUG(dbgs() << "Ignoring dep " << GVU->getName() << " -> "
                         << GV.getName() << "\n");
       continue;
     }
+
     GVDependencies[GVU].insert(&GV);
   }
 }
Index: llvm/test/Transforms/GlobalDCE/virtual-functions-swift.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/GlobalDCE/virtual-functions-swift.ll
@@ -0,0 +1,48 @@
+; RUN: opt < %s -globaldce -S
+; RUN: opt < %s -globaldce -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata)
+
+; A vtable with "relative pointers", slots don't contain pointers to implementations, but instead have an i32 offset from the vtable itself to the implementation.
+@vtable = internal unnamed_addr constant { [3 x i32] } { [3 x i32] [
+  i32 trunc (i64 sub (i64 ptrtoint (void ()* @vfunc1_live              to i64), i64 ptrtoint ({ [3 x i32] }* @vtable to i64)) to i32),
+  i32 trunc (i64 sub (i64 ptrtoint (void ()* @vfunc2_dead              to i64), i64 ptrtoint ({ [3 x i32] }* @vtable to i64)) to i32),
+  i32 trunc (i64 sub (i64 ptrtoint (void ()* @regular_non_virtual_func to i64), i64 ptrtoint ({ [3 x i32] }* @vtable to i64)) to i32)
+]}, align 8, !type !0, !type !1, !vcall_visibility !{i64 2}
+!0 = !{i64 0, !"vfunc1.type"}
+!1 = !{i64 4, !"vfunc2.type"}
+
+; CHECK:      @vtable = internal unnamed_addr constant { [3 x i32] } { [3 x i32] [
+; CHECK-SAME:   i32 trunc (i64 sub (i64 ptrtoint (void ()* @vfunc1_live              to i64), i64 ptrtoint ({ [3 x i32] }* @vtable to i64)) to i32),
+; CHECK-SAME:   i32 trunc (i64 sub (i64 0,                                                    i64 ptrtoint ({ [3 x i32] }* @vtable to i64)) to i32),
+; CHECK-SAME:   i32 trunc (i64 sub (i64 ptrtoint (void ()* @regular_non_virtual_func to i64), i64 ptrtoint ({ [3 x i32] }* @vtable to i64)) to i32)
+; CHECK-SAME: ] }, align 8, !type !0, !type !1, !vcall_visibility !2
+
+; (1) vfunc1_live is referenced from @main, stays alive
+define internal void @vfunc1_live() {
+  ; CHECK: define internal void @vfunc1_live(
+  ret void
+}
+
+; (2) vfunc2_dead is never referenced, gets removed and vtable slot is null'd
+define internal void @vfunc2_dead() {
+  ; CHECK-NOT: define internal void @vfunc2_dead(
+  ret void
+}
+
+; (3) regular, non-virtual function that just happens to be referenced from the vtable data structure, should stay alive
+define internal void @regular_non_virtual_func() {
+  ; CHECK: define internal void @regular_non_virtual_func(
+  ret void
+}
+
+define void @main() {
+  %1 = ptrtoint { [3 x i32] }* @vtable to i64 ; to keep @vtable alive
+  %2 = tail call { i8*, i1 } @llvm.type.checked.load(i8* null, i32 0, metadata !"vfunc1.type")
+  ret void
+}
+
+!999 = !{i32 1, !"Virtual Function Elim", i32 1}
+!llvm.module.flags = !{!999}