diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -5084,7 +5084,8 @@
 used for call site debug info. The ``retainedNodes:`` field is a list of
 :ref:`variables <DILocalVariable>` and :ref:`labels <DILabel>` that must be
 retained, even if their IR counterparts are optimized out of the IR. The
-``type:`` field must point at an :ref:`DISubroutineType`.
+``type:`` field is optional, but if present it must point at a
+:ref:`DISubroutineType`.
 
 .. _DISubprogramDeclaration:
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -927,15 +927,17 @@
   }
 
   // If this is a variadic function, add an unspecified parameter.
-  DITypeRefArray FnArgs = Sub->getType()->getTypeArray();
-
-  // If we have a single element of null, it is a function that returns void.
-  // If we have more than one elements and the last one is null, it is a
-  // variadic function.
-  if (FnArgs.size() > 1 && !FnArgs[FnArgs.size() - 1] &&
-      !includeMinimalInlineScopes())
-    ScopeDIE.addChild(
-        DIE::get(DIEValueAllocator, dwarf::DW_TAG_unspecified_parameters));
+  if (DISubroutineType *FnType = Sub->getType()) {
+    DITypeRefArray FnArgs = FnType->getTypeArray();
+
+    // If we have a single element of null, it is a function that returns void.
+    // If we have more than one elements and the last one is null, it is a
+    // variadic function.
+    if (FnArgs.size() > 1 && !FnArgs[FnArgs.size() - 1] &&
+        !includeMinimalInlineScopes())
+      ScopeDIE.addChild(
+          DIE::get(DIEValueAllocator, dwarf::DW_TAG_unspecified_parameters));
+  }
 
   return ScopeDIE;
 }
diff --git a/llvm/test/CodeGen/Generic/disubprogram-no-type.ll b/llvm/test/CodeGen/Generic/disubprogram-no-type.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/Generic/disubprogram-no-type.ll
@@ -0,0 +1,16 @@
+; RUN: llc %s -filetype=obj -o - | llvm-dwarfdump - | FileCheck %s
+
+; Confirm we don't ICE when generating DWARF debug information for a
+; DISubprogram that is missing a `type:`
+
+; CHECK-NOT: DW_AT_type
+
+define i32 @f(i32 %0) !dbg !3 { ret i32 %0 }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2}
+
+!0 = distinct !DICompileUnit(language: 0, file: !1, emissionKind: FullDebug)
+!1 = !DIFile(filename: "-", directory: "")
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = distinct !DISubprogram(file: !1, unit: !0)