diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -1670,13 +1670,12 @@
       NormalizedValues<["None", "Global"]>,
       MarshallingInfoEnum<CodeGenOpts<"SanitizeAddressDtor">, "Global">;
 defm sanitize_memory_param_retval
-  : BoolOption<"f", "sanitize-memory-param-retval",
-      CodeGenOpts<"SanitizeMemoryParamRetval">,
-      DefaultFalse,
-      PosFlag<SetTrue, [CC1Option], "Enable">, NegFlag<SetFalse, [], "Disable">,
-      BothFlags<[], " detection of uninitialized parameters and return values">>,
-    Group<f_clang_Group>;
-// Note: This flag was introduced when it was necessary to distinguish between
+    : BoolFOption<"sanitize-memory-param-retval",
+        CodeGenOpts<"SanitizeMemoryParamRetval">,
+        DefaultFalse,
+        PosFlag<SetTrue, [CC1Option], "Enable">, NegFlag<SetFalse, [], "Disable">,
+        BothFlags<[], " detection of uninitialized parameters and return values">>;
+//// Note: This flag was introduced when it was necessary to distinguish between
 //       ABI for correct codegen.  This is no longer needed, but the flag is
 //       not removed since targeting either ABI will behave the same.
 //       This way we cause no disturbance to existing scripts & code, and if we
@@ -5399,7 +5398,8 @@
   BothFlags<[], " the Clang AST before running backend code generation">>;
 def enable_noundef_analysis : Flag<["-"], "enable-noundef-analysis">, Group<f_Group>,
   HelpText<"Enable analyzing function argument and return types for mandatory definedness">,
-  MarshallingInfoFlag<CodeGenOpts<"EnableNoundefAttrs">>;
+  MarshallingInfoFlag<CodeGenOpts<"EnableNoundefAttrs">>,
+  ImpliedByAnyOf<[fsanitize_memory_param_retval.KeyPath]>;
 def discard_value_names : Flag<["-"], "discard-value-names">,
   HelpText<"Discard value names in LLVM IR">,
   MarshallingInfoFlag<CodeGenOpts<"DiscardValueNames">>;
diff --git a/clang/test/CodeGen/attr-noundef.cpp b/clang/test/CodeGen/attr-noundef.cpp
--- a/clang/test/CodeGen/attr-noundef.cpp
+++ b/clang/test/CodeGen/attr-noundef.cpp
@@ -1,5 +1,11 @@
 // RUN: %clang -cc1 -triple x86_64-gnu-linux -x c++ -S -emit-llvm -enable-noundef-analysis %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-INTEL
 // RUN: %clang -cc1 -triple aarch64-gnu-linux -x c++ -S -emit-llvm -enable-noundef-analysis %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-AARCH
+// RUN: %clang -cc1 -triple x86_64-gnu-linux -x c++ -S -emit-llvm -fsanitize-memory-param-retval %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-INTEL
+// RUN: %clang -cc1 -triple aarch64-gnu-linux -x c++ -S -emit-llvm -fsanitize-memory-param-retval %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-AARCH
+
+// no-sanitize-memory-param-retval does NOT conflict with enable-noundef-analysis
+// RUN: %clang -cc1 -triple x86_64-gnu-linux -x c++ -S -emit-llvm -enable-noundef-analysis -fno-sanitize-memory-param-retval %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-INTEL
+// RUN: %clang -cc1 -triple x86_64-gnu-linux -x c++ -S -emit-llvm -fno-sanitize-memory-param-retval -enable-noundef-analysis %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-INTEL
 
 //************ Passing structs by value
 // TODO: No structs may currently be marked noundef
diff --git a/clang/test/CodeGen/indirect-noundef.cpp b/clang/test/CodeGen/indirect-noundef.cpp
--- a/clang/test/CodeGen/indirect-noundef.cpp
+++ b/clang/test/CodeGen/indirect-noundef.cpp
@@ -1,4 +1,9 @@
 // RUN: %clang -cc1 -x c++ -triple x86_64-unknown-unknown -O0 -emit-llvm -enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang -cc1 -x c++ -triple x86_64-unknown-unknown -O0 -emit-llvm -fsanitize-memory-param-retval -o - %s | FileCheck %s
+
+// no-sanitize-memory-param-retval does NOT conflict with enable-noundef-analysis
+// RUN: %clang -cc1 -x c++ -triple x86_64-unknown-unknown -O0 -emit-llvm -fno-sanitize-memory-param-retval -enable-noundef-analysis -o - %s | FileCheck %s
+// RUN: %clang -cc1 -x c++ -triple x86_64-unknown-unknown -O0 -emit-llvm -enable-noundef-analysis -fno-sanitize-memory-param-retval -o - %s | FileCheck %s
 
 union u1 {
   int val;
diff --git a/clang/test/CodeGen/msan-param-retval.c b/clang/test/CodeGen/msan-param-retval.c
--- a/clang/test/CodeGen/msan-param-retval.c
+++ b/clang/test/CodeGen/msan-param-retval.c
@@ -5,7 +5,7 @@
 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -fsanitize=memory -Xclang -enable-noundef-analysis -mllvm -msan-eager-checks -o - %s | \
 // RUN:     FileCheck %s --check-prefixes=NOUNDEF,EAGER
 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -fsanitize=memory -fsanitize-memory-param-retval -o - %s | \
-// RUN:     FileCheck %s --check-prefixes=CLEAN
+// RUN:     FileCheck %s --check-prefixes=NOUNDEF,EAGER
 // RUN: %clang -target x86_64-linux-gnu -S -emit-llvm -fsanitize=memory -Xclang -enable-noundef-analysis -fsanitize-memory-param-retval -o - %s | \
 // RUN:     FileCheck %s --check-prefixes=NOUNDEF,EAGER
 
diff --git a/compiler-rt/test/msan/noundef_analysis.cpp b/compiler-rt/test/msan/noundef_analysis.cpp
--- a/compiler-rt/test/msan/noundef_analysis.cpp
+++ b/compiler-rt/test/msan/noundef_analysis.cpp
@@ -2,6 +2,8 @@
 // RUN: FileCheck %s --check-prefix=MISSED --allow-empty < %t.out
 // RUN: %clangxx_msan %s -Xclang -enable-noundef-analysis -mllvm -msan-eager-checks=1 -o %t && not %run %t >%t.out 2>&1
 // RUN: FileCheck %s < %t.out
+// RUN: %clangxx_msan %s -fsanitize-memory-param-retval -o %t && not %run %t >%t.out 2>&1
+// RUN: FileCheck %s < %t.out
 
 struct SimpleStruct {
   int md1;