Index: mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
===================================================================
--- mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
+++ mlir/include/mlir/Dialect/LLVMIR/LLVMIntrinsicOps.td
@@ -186,6 +186,25 @@
   let assemblyFormat = "$handle attr-dict";
 }
 
+//
+// Variadic function intrinsics.
+//
+
+def LLVM_VaStartOp : LLVM_ZeroResultIntrOp<"vastart">,
+                     Arguments<(ins LLVM_i8Ptr:$arg_list)> {
+  let assemblyFormat = "$arg_list attr-dict";
+}
+
+def LLVM_VaCopyOp : LLVM_ZeroResultIntrOp<"vacopy">,
+                    Arguments<(ins LLVM_i8Ptr:$dest_list, LLVM_i8Ptr:$src_list)> {
+  let assemblyFormat = "$src_list `to` $dest_list attr-dict";
+}
+
+def LLVM_VaEndOp : LLVM_ZeroResultIntrOp<"vaend">,
+                   Arguments<(ins LLVM_i8Ptr:$arg_list)> {
+  let assemblyFormat = "$arg_list attr-dict";
+}
+
 //
 // Exception handling intrinsics.
 //
@@ -548,4 +567,4 @@
 def LLVM_VPPtrToIntOp : LLVM_VPCastPtr<"ptrtoint">;
 def LLVM_VPIntToPtrOp : LLVM_VPCastI<"inttoptr">;
 
-#endif // LLVM_INTRINSIC_OPS
\ No newline at end of file
+#endif // LLVM_INTRINSIC_OPS
Index: mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
===================================================================
--- mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
+++ mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp
@@ -2311,9 +2311,6 @@
     return success();
   }
 
-  if (isVarArg())
-    return emitOpError("only external functions can be variadic");
-
   return success();
 }
 
Index: mlir/test/Dialect/LLVMIR/func.mlir
===================================================================
--- mlir/test/Dialect/LLVMIR/func.mlir
+++ mlir/test/Dialect/LLVMIR/func.mlir
@@ -159,6 +159,11 @@
   llvm.func weak fastcc @cconv3() {
     llvm.return
   }
+
+  // CHECK-LABEL: llvm.func @variadic_def
+  llvm.func @variadic_def(...) {
+    llvm.return
+  }
 }
 
 // -----
@@ -232,15 +237,6 @@
 
 // -----
 
-module {
-  // expected-error@+1 {{only external functions can be variadic}}
-  llvm.func @variadic_def(...) {
-    llvm.return
-  }
-}
-
-// -----
-
 module {
   // expected-error@+1 {{cannot attach result attributes to functions with a void return}}
   llvm.func @variadic_def() -> (!llvm.void {llvm.noalias})
Index: mlir/test/Target/LLVMIR/Import/intrinsic.ll
===================================================================
--- mlir/test/Target/LLVMIR/Import/intrinsic.ll
+++ mlir/test/Target/LLVMIR/Import/intrinsic.ll
@@ -385,6 +385,17 @@
   ret void
 }
 
+; CHECK-LABEL: llvm.func @va_intrinsics_test
+define void @va_intrinsics_test(i8* %0, i8* %1) {
+; CHECK: llvm.intr.vastart %{{.*}}
+  call void @llvm.va_start(i8* %0)
+; CHECK: llvm.intr.vacopy %{{.*}} to %{{.*}}
+  call void @llvm.va_copy(i8* %1, i8* %0)
+; CHECK: llvm.intr.vaend %{{.*}}
+  call void @llvm.va_end(i8* %0)
+  ret void
+}
+
 ; CHECK-LABEL:  llvm.func @coro_id
 define void @coro_id(i32 %0, i8* %1) {
   ; CHECK: llvm.intr.coro.id %{{.*}}, %{{.*}}, %{{.*}}, %{{.*}} : !llvm.token
@@ -686,6 +697,9 @@
 declare i32 @llvm.eh.typeid.for(i8*)
 declare i8* @llvm.stacksave()
 declare void @llvm.stackrestore(i8*)
+declare void @llvm.va_start(i8*)
+declare void @llvm.va_copy(i8*, i8*)
+declare void @llvm.va_end(i8*)
 declare <8 x i32> @llvm.vp.add.v8i32(<8 x i32>, <8 x i32>, <8 x i1>, i32)
 declare <8 x i32> @llvm.vp.sub.v8i32(<8 x i32>, <8 x i32>, <8 x i1>, i32)
 declare <8 x i32> @llvm.vp.mul.v8i32(<8 x i32>, <8 x i32>, <8 x i1>, i32)