Index: llvm/lib/CodeGen/LiveDebugValues.cpp
===================================================================
--- llvm/lib/CodeGen/LiveDebugValues.cpp
+++ llvm/lib/CodeGen/LiveDebugValues.cpp
@@ -1840,14 +1840,16 @@
   MachineBasicBlock &First_MBB = *(MF.begin());
   for (auto &MI : First_MBB) {
     collectRegDefs(MI, DefinedRegs, TRI);
-      if (MI.isDebugValue())
-        recordEntryValue(MI, DefinedRegs, OpenRanges, VarLocIDs);
+    // We might already have generated the entry values within deadargelim,
+    // so we don't consider these as candidates for entry values anymore.
+    if (MI.isDebugValue() && !MI.isDebugEntryValue())
+      recordEntryValue(MI, DefinedRegs, OpenRanges, VarLocIDs);
   }
 
   // Initialize per-block structures and scan for fragment overlaps.
   for (auto &MBB : MF)
     for (auto &MI : MBB)
-      if (MI.isDebugValue())
+      if (MI.isDebugValue() && !MI.isDebugEntryValue())
         accumulateFragmentMap(MI, SeenFragments, OverlapFragments);
 
   auto hasNonArtificialLocation = [](const MachineInstr &MI) -> bool {
Index: llvm/lib/IR/Verifier.cpp
===================================================================
--- llvm/lib/IR/Verifier.cpp
+++ llvm/lib/IR/Verifier.cpp
@@ -5431,8 +5431,6 @@
   // We don't know whether this intrinsic verified correctly.
   if (!E || !E->isValid())
     return;
-
-  AssertDI(!E->isEntryValue(), "Entry values are only allowed in MIR", &I);
 }
 
 void Verifier::verifyCompileUnits() {
Index: llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
===================================================================
--- llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
+++ llvm/lib/Transforms/IPO/DeadArgumentElimination.cpp
@@ -23,6 +23,7 @@
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRBuilder.h"
@@ -45,6 +46,7 @@
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include <cassert>
 #include <cstdint>
 #include <utility>
@@ -291,7 +293,16 @@
     if (!Arg.hasSwiftErrorAttr() && Arg.use_empty() &&
         !Arg.hasPassPointeeByValueCopyAttr()) {
       if (Arg.isUsedByMetadata()) {
-        Arg.replaceAllUsesWith(UndefValue::get(Arg.getType()));
+        // Create entry values for unused args.
+        SmallVector<DbgValueInst *, 1> DbgValues;
+        findDbgValues(DbgValues, &Arg);
+        for (auto *DVI : DbgValues) {
+          DIExpression *NewExpr = DIExpression::prepend(
+              DVI->getExpression(), DIExpression::EntryValue);
+          DVI->setArgOperand(
+              2, MetadataAsValue::get(Arg.getType()->getContext(), NewExpr));
+        }
+
         Changed = true;
       }
       UnusedArgs.push_back(Arg.getArgNo());
Index: llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll
===================================================================
--- llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll
+++ llvm/test/Transforms/DeadArgElim/dbginfo-update-dbgval.ll
@@ -24,7 +24,7 @@
 ; Function Attrs: noinline nounwind uwtable
 define dso_local void @f2(i32 %k) local_unnamed_addr !dbg !11 {
 entry:
-; CHECK: call void @llvm.dbg.value(metadata i32 undef, metadata !15, metadata !DIExpression()), !dbg !16
+; CHECK: call void @llvm.dbg.value(metadata i32 %k, metadata !15, metadata !DIExpression(DW_OP_LLVM_entry_value, 1)), !dbg !16
   call void @llvm.dbg.value(metadata i32 %k, metadata !15, metadata !DIExpression()), !dbg !16
   %0 = load i32, i32* @s, align 4, !dbg !17
   %inc = add nsw i32 %0, 1, !dbg !17
Index: llvm/test/Verifier/diexpression-entry-value-llvm-ir.ll
===================================================================
--- llvm/test/Verifier/diexpression-entry-value-llvm-ir.ll
+++ /dev/null
@@ -1,31 +0,0 @@
-; RUN: llvm-as -disable-output <%s 2>&1| FileCheck %s
-
-; The DW_OP_LLVM_entry_value operation can only be used in MIR.
-
-; CHECK: Entry values are only allowed in MIR
-; CHECK: call void @llvm.dbg.value(metadata i32 %param, metadata !{{.*}}, metadata !DIExpression(DW_OP_LLVM_entry_value, 1))
-; CHECK: warning: ignoring invalid debug info
-
-define void @foo(i32 %param) !dbg !4 {
-entry:
-  call void @llvm.dbg.value(metadata i32 %param, metadata !8, metadata !DIExpression(DW_OP_LLVM_entry_value, 1)), !dbg !9
-  ret void
-}
-
-declare void @llvm.dbg.value(metadata, metadata, metadata) #0
-
-attributes #0 = { nounwind readnone speculatable willreturn }
-
-!llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!2, !3}
-
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, emissionKind: FullDebug)
-!1 = !DIFile(filename: "a.c", directory: "/")
-!2 = !{i32 2, !"Dwarf Version", i32 4}
-!3 = !{i32 2, !"Debug Info Version", i32 3}
-!4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, type: !5, unit: !0)
-!5 = !DISubroutineType(types: !6)
-!6 = !{null, !7}
-!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
-!8 = !DILocalVariable(name: "param", arg: 1, scope: !4, file: !1, type: !7)
-!9 = !DILocation(line: 0, scope: !4)