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
@@ -4583,6 +4583,8 @@
 def mno_reference_types : Flag<["-"], "mno-reference-types">, Group<m_wasm_Features_Group>;
 def mextended_const : Flag<["-"], "mextended-const">, Group<m_wasm_Features_Group>;
 def mno_extended_const : Flag<["-"], "mno-extended-const">, Group<m_wasm_Features_Group>;
+def mmultimemory : Flag<["-"], "mmultimemory">, Group<m_wasm_Features_Group>;
+def mno_multimemory : Flag<["-"], "mno-multimemory">, Group<m_wasm_Features_Group>;
 def mexec_model_EQ : Joined<["-"], "mexec-model=">, Group<m_wasm_Features_Driver_Group>,
                      Values<"command,reactor">,
                      HelpText<"Execution model (WebAssembly only)">,
diff --git a/clang/lib/Basic/Targets/WebAssembly.h b/clang/lib/Basic/Targets/WebAssembly.h
--- a/clang/lib/Basic/Targets/WebAssembly.h
+++ b/clang/lib/Basic/Targets/WebAssembly.h
@@ -63,6 +63,7 @@
   bool HasTailCall = false;
   bool HasReferenceTypes = false;
   bool HasExtendedConst = false;
+  bool HasMultiMemory = false;
 
   std::string ABI;
 
diff --git a/clang/lib/Basic/Targets/WebAssembly.cpp b/clang/lib/Basic/Targets/WebAssembly.cpp
--- a/clang/lib/Basic/Targets/WebAssembly.cpp
+++ b/clang/lib/Basic/Targets/WebAssembly.cpp
@@ -57,6 +57,7 @@
       .Case("tail-call", HasTailCall)
       .Case("reference-types", HasReferenceTypes)
       .Case("extended-const", HasExtendedConst)
+      .Case("multimemory", HasMultiMemory)
       .Default(false);
 }
 
@@ -96,6 +97,8 @@
     Builder.defineMacro("__wasm_reference_types__");
   if (HasExtendedConst)
     Builder.defineMacro("__wasm_extended_const__");
+  if (HasMultiMemory)
+    Builder.defineMacro("__wasm_multimemory__");
 
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");
@@ -152,6 +155,7 @@
     Features["mutable-globals"] = true;
     Features["tail-call"] = true;
     Features["reference-types"] = true;
+    Features["multimemory"] = true;
     setSIMDLevel(Features, SIMD128, true);
   } else if (CPU == "generic") {
     Features["sign-ext"] = true;
@@ -260,6 +264,14 @@
       HasExtendedConst = false;
       continue;
     }
+    if (Feature == "+multimemory") {
+      HasMultiMemory = true;
+      continue;
+    }
+    if (Feature == "-multimemory") {
+      HasMultiMemory = false;
+      continue;
+    }
 
     Diags.Report(diag::err_opt_not_valid_with_opt)
         << Feature << "-target-feature";
diff --git a/clang/test/Driver/wasm-features.c b/clang/test/Driver/wasm-features.c
--- a/clang/test/Driver/wasm-features.c
+++ b/clang/test/Driver/wasm-features.c
@@ -41,3 +41,12 @@
 // DEFAULT-NOT: "-target-feature" "-nontrapping-fptoint"
 // MVP-NOT: "-target-feature" "+nontrapping-fptoint"
 // BLEEDING-EDGE-NOT: "-target-feature" "-nontrapping-fptoint"
+
+// RUN: %clang --target=wasm32-unknown-unknown -### %s -mmultimemory 2>&1 | FileCheck %s -check-prefix=MULTIMEMORY
+// RUN: %clang --target=wasm32-unknown-unknown -### %s -mno-multimemory 2>&1 | FileCheck %s -check-prefix=NO-MULTIMEMORY
+
+// MULTIMEMORY: "-target-feature" "+multimemory"
+// NO-MULTIMEMORY: "-target-feature" "-multimemory"
+// DEFAULT-NOT: "-target-feature" "-multimemory"
+// MVP-NOT: "-target-feature" "+multimemory"
+// BLEEDING-EDGE-NOT: "-target-feature" "-multimemory"
diff --git a/clang/test/Preprocessor/wasm-target-features.c b/clang/test/Preprocessor/wasm-target-features.c
--- a/clang/test/Preprocessor/wasm-target-features.c
+++ b/clang/test/Preprocessor/wasm-target-features.c
@@ -114,6 +114,16 @@
 // RUN:   | FileCheck %s -check-prefix=EXTENDED-CONST
 //
 // EXTENDED-CONST:#define __wasm_extended_const__ 1{{$}}
+//
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm32-unknown-unknown -mmultimemory \
+// RUN:   | FileCheck %s -check-prefix=MULTIMEMORY
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm64-unknown-unknown -mmultimemory \
+// RUN:   | FileCheck %s -check-prefix=MULTIMEMORY
+//
+// MULTIMEMORY:#define __wasm_multimemory__ 1{{$}}
+//
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=mvp \
@@ -133,6 +143,7 @@
 // MVP-NOT:#define __wasm_tail_call__
 // MVP-NOT:#define __wasm_reference_types__
 // MVP-NOT:#define __wasm_extended_const__
+// MVP-NOT:#define __wasm_multimemory__
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge \
@@ -148,6 +159,7 @@
 // BLEEDING-EDGE-DAG:#define __wasm_atomics__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_mutable_globals__ 1{{$}}
 // BLEEDING-EDGE-DAG:#define __wasm_tail_call__ 1{{$}}
+// BLEEDING-EDGE-DAG:#define __wasm_multimemory__ 1{{$}}
 // BLEEDING-EDGE-NOT:#define __wasm_unimplemented_simd128__ 1{{$}}
 // BLEEDING-EDGE-NOT:#define __wasm_exception_handling__ 1{{$}}
 // BLEEDING-EDGE-NOT:#define __wasm_multivalue__ 1{{$}}
diff --git a/llvm/lib/Target/WebAssembly/WebAssembly.td b/llvm/lib/Target/WebAssembly/WebAssembly.td
--- a/llvm/lib/Target/WebAssembly/WebAssembly.td
+++ b/llvm/lib/Target/WebAssembly/WebAssembly.td
@@ -71,6 +71,10 @@
       SubtargetFeature<"extended-const", "HasExtendedConst", "true",
                        "Enable extended const expressions">;
 
+def FeatureMultiMemory :
+      SubtargetFeature<"multimemory", "HasMultiMemory", "true",
+                       "Enable multiple memories">;
+
 //===----------------------------------------------------------------------===//
 // Architectures.
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
@@ -70,6 +70,10 @@
     Predicate<"Subtarget->hasExtendedConst()">,
     AssemblerPredicate<(all_of FeatureExtendedConst), "extended-const">;
 
+def HasMultiMemory :
+    Predicate<"Subtarget->hasMultiMemory()">,
+    AssemblerPredicate<(all_of FeatureMultiMemory), "multimemory">;
+
 //===----------------------------------------------------------------------===//
 // WebAssembly-specific DAG Node Types.
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h b/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h
--- a/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h
@@ -49,6 +49,7 @@
   bool HasTailCall = false;
   bool HasReferenceTypes = false;
   bool HasExtendedConst = false;
+  bool HasMultiMemory = false;
 
   /// What processor and OS we're targeting.
   Triple TargetTriple;
@@ -101,6 +102,7 @@
   bool hasMutableGlobals() const { return HasMutableGlobals; }
   bool hasTailCall() const { return HasTailCall; }
   bool hasReferenceTypes() const { return HasReferenceTypes; }
+  bool hasMultiMemory() const { return HasMultiMemory; }
 
   /// Parses features string setting specified subtarget options. Definition of
   /// function is auto generated by tblgen.