diff --git a/llvm/lib/IR/Attributes.cpp b/llvm/lib/IR/Attributes.cpp
--- a/llvm/lib/IR/Attributes.cpp
+++ b/llvm/lib/IR/Attributes.cpp
@@ -1859,6 +1859,10 @@
         .addByValAttr(Ty)
         .addByRefAttr(Ty);
 
+  // Some attributes can apply to all "values" but there are no `void` values.
+  if (Ty->isVoidTy())
+    Incompatible.addAttribute(Attribute::NoUndef);
+
   return Incompatible;
 }
 
diff --git a/llvm/test/Transforms/DeadArgElim/returned.ll b/llvm/test/Transforms/DeadArgElim/returned.ll
--- a/llvm/test/Transforms/DeadArgElim/returned.ll
+++ b/llvm/test/Transforms/DeadArgElim/returned.ll
@@ -45,7 +45,7 @@
 
 ; Drop all these attributes
 ; CHECK-LABEL: define internal void @test6
-define internal align 8 dereferenceable_or_null(2) noalias i8* @test6() {
+define internal align 8 dereferenceable_or_null(2) noundef noalias i8* @test6() {
   ret i8* null
 }
 
diff --git a/llvm/test/Verifier/align.ll b/llvm/test/Verifier/align.ll
--- a/llvm/test/Verifier/align.ll
+++ b/llvm/test/Verifier/align.ll
@@ -6,7 +6,7 @@
   ret void
 }
 
-; CHECK: Wrong types for attribute: inalloca nest noalias nocapture nonnull readnone readonly signext zeroext byref(void) byval(void) preallocated(void) sret(void) align 1 dereferenceable(1) dereferenceable_or_null(1)
+; CHECK: Wrong types for attribute: inalloca nest noalias nocapture noundef nonnull readnone readonly signext zeroext byref(void) byval(void) preallocated(void) sret(void) align 1 dereferenceable(1) dereferenceable_or_null(1)
 ; CHECK-NEXT: @align_non_pointer2
 define align 4 void @align_non_pointer2(i32 %a) {
   ret void
diff --git a/llvm/test/Verifier/noundef.ll b/llvm/test/Verifier/noundef.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Verifier/noundef.ll
@@ -0,0 +1,7 @@
+; RUN: not llvm-as < %s -o /dev/null 2>&1 | FileCheck %s
+
+; CHECK: Wrong types for attribute: inalloca nest noalias nocapture noundef nonnull readnone readonly signext zeroext byref(void) byval(void) preallocated(void) sret(void) align 1 dereferenceable(1) dereferenceable_or_null(1)
+; CHECK-NEXT: @noundef_void
+define noundef void @noundef_void() {
+  ret void
+}