diff --git a/lib/Target/WebAssembly/WebAssembly.td b/lib/Target/WebAssembly/WebAssembly.td
index 99cf1f119a20..76b3ddbbfffa 100644
--- a/lib/Target/WebAssembly/WebAssembly.td
+++ b/lib/Target/WebAssembly/WebAssembly.td
@@ -32,6 +32,11 @@ def FeatureNontrappingFPToInt :
                        "HasNontrappingFPToInt", "true",
                        "Enable non-trapping float-to-int conversion operators">;
 
+def FeatureSignExt :
+      SubtargetFeature<"sign-ext",
+                       "HasSignExt", "true",
+                       "Enable sign extension operators">;
+
 //===----------------------------------------------------------------------===//
 // Architectures.
 //===----------------------------------------------------------------------===//
diff --git a/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 299009fa6674..d0b3ad371191 100644
--- a/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -117,8 +117,7 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
   // As a special case, these operators use the type to mean the type to
   // sign-extend from.
   setOperationAction(ISD::SIGN_EXTEND_INREG, MVT::i1, Expand);
-  if (!Subtarget->hasAtomics()) {
-    // The Atomics feature includes signext intructions.
+  if (!Subtarget->hasSignExt()) {
     for (auto T : {MVT::i8, MVT::i16, MVT::i32})
       setOperationAction(ISD::SIGN_EXTEND_INREG, T, Expand);
   }
diff --git a/lib/Target/WebAssembly/WebAssemblyInstrConv.td b/lib/Target/WebAssembly/WebAssemblyInstrConv.td
index 426c2c802172..bf1282b5edfa 100644
--- a/lib/Target/WebAssembly/WebAssemblyInstrConv.td
+++ b/lib/Target/WebAssembly/WebAssemblyInstrConv.td
@@ -26,7 +26,7 @@ def I64_EXTEND_U_I32 : I<(outs I64:$dst), (ins I32:$src),
                          [(set I64:$dst, (zext I32:$src))],
                          "i64.extend_u/i32\t$dst, $src", 0xad>;
 
-let Predicates = [HasAtomics] in {
+let Predicates = [HasSignExt] in {
 def I32_EXTEND8_S_I32 : I<(outs I32:$dst), (ins I32:$src),
                           [(set I32:$dst, (sext_inreg I32:$src, i8))],
                           "i32.extend8_s\t$dst, $src", 0xc0>;
@@ -42,7 +42,7 @@ def I64_EXTEND16_S_I64 : I<(outs I64:$dst), (ins I64:$src),
 def I64_EXTEND32_S_I64 : I<(outs I64:$dst), (ins I64:$src),
                            [(set I64:$dst, (sext_inreg I64:$src, i32))],
                            "i64.extend32_s\t$dst, $src", 0xc4>;
-} // Predicates = [HasAtomics]
+} // Predicates = [HasSignExt]
 
 } // defs = [ARGUMENTS]
 
diff --git a/lib/Target/WebAssembly/WebAssemblyInstrInfo.td b/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
index f8d311ac3b00..245d5abbf263 100644
--- a/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
+++ b/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
@@ -30,6 +30,14 @@ def NotHasNontrappingFPToInt :
     Predicate<"!Subtarget->hasNontrappingFPToInt()">,
               AssemblerPredicate<"!FeatureNontrappingFPToInt",
                                  "nontrapping-fptoint">;
+def HasSignExt :
+    Predicate<"Subtarget->hasSignExt()">,
+              AssemblerPredicate<"FeatureSignExt",
+                                 "sign-ext">;
+def NotHasSignExt :
+    Predicate<"!Subtarget->hasSignExt()">,
+              AssemblerPredicate<"!FeatureSignExt",
+                                 "sign-ext">;
 
 //===----------------------------------------------------------------------===//
 // WebAssembly-specific DAG Node Types.
diff --git a/lib/Target/WebAssembly/WebAssemblySubtarget.cpp b/lib/Target/WebAssembly/WebAssemblySubtarget.cpp
index 9e122a5f1574..78602a35e649 100644
--- a/lib/Target/WebAssembly/WebAssemblySubtarget.cpp
+++ b/lib/Target/WebAssembly/WebAssemblySubtarget.cpp
@@ -41,8 +41,8 @@ WebAssemblySubtarget::WebAssemblySubtarget(const Triple &TT,
                                            const std::string &FS,
                                            const TargetMachine &TM)
     : WebAssemblyGenSubtargetInfo(TT, CPU, FS), HasSIMD128(false),
-      HasAtomics(false), HasNontrappingFPToInt(false), CPUString(CPU),
-      TargetTriple(TT), FrameLowering(),
+      HasAtomics(false), HasNontrappingFPToInt(false), HasSignExt(false),
+      CPUString(CPU), TargetTriple(TT), FrameLowering(),
       InstrInfo(initializeSubtargetDependencies(FS)), TSInfo(),
       TLInfo(TM, *this) {}
 
diff --git a/lib/Target/WebAssembly/WebAssemblySubtarget.h b/lib/Target/WebAssembly/WebAssemblySubtarget.h
index a6bf0b6d54f6..c999f501a9c9 100644
--- a/lib/Target/WebAssembly/WebAssemblySubtarget.h
+++ b/lib/Target/WebAssembly/WebAssemblySubtarget.h
@@ -32,6 +32,7 @@ class WebAssemblySubtarget final : public WebAssemblyGenSubtargetInfo {
   bool HasSIMD128;
   bool HasAtomics;
   bool HasNontrappingFPToInt;
+  bool HasSignExt;
 
   /// String name of used CPU.
   std::string CPUString;
@@ -78,6 +79,7 @@ class WebAssemblySubtarget final : public WebAssemblyGenSubtargetInfo {
   bool hasSIMD128() const { return HasSIMD128; }
   bool hasAtomics() const { return HasAtomics; }
   bool hasNontrappingFPToInt() const { return HasNontrappingFPToInt; }
+  bool hasSignExt() const { return HasSignExt; }
 
   /// Parses features string setting specified subtarget options. Definition of
   /// function is auto generated by tblgen.
diff --git a/test/CodeGen/WebAssembly/load-ext-atomic.ll b/test/CodeGen/WebAssembly/load-ext-atomic.ll
index 0c4552dc9afb..862f29583a9b 100644
--- a/test/CodeGen/WebAssembly/load-ext-atomic.ll
+++ b/test/CodeGen/WebAssembly/load-ext-atomic.ll
@@ -1,4 +1,4 @@
-; RUN: llc < %s -mattr=+atomics -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s
+; RUN: llc < %s -mattr=+atomics,+sign-ext -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s
 
 ; Test that extending loads are assembled properly.
 
diff --git a/test/CodeGen/WebAssembly/offset-atomics.ll b/test/CodeGen/WebAssembly/offset-atomics.ll
index 24727fc2608d..3415f07a81e3 100644
--- a/test/CodeGen/WebAssembly/offset-atomics.ll
+++ b/test/CodeGen/WebAssembly/offset-atomics.ll
@@ -1,5 +1,5 @@
 ; RUN: not llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals -mattr=+atomics | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals -mattr=+atomics,+sign-ext | FileCheck %s
 
 ; Test that atomic loads are assembled properly.
 
diff --git a/test/CodeGen/WebAssembly/signext-inreg.ll b/test/CodeGen/WebAssembly/signext-inreg.ll
index c97a1bf1b0e8..00637f10eb91 100644
--- a/test/CodeGen/WebAssembly/signext-inreg.ll
+++ b/test/CodeGen/WebAssembly/signext-inreg.ll
@@ -1,5 +1,5 @@
-; RUN: llc < %s -mattr=+atomics -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s --check-prefix=NOATOMIC
+; RUN: llc < %s -mattr=+sign-ext -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | FileCheck %s --check-prefix=NOSIGNEXT
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown-wasm"
@@ -10,8 +10,8 @@ target triple = "wasm32-unknown-unknown-wasm"
 ; CHECK-NEXT: i32.extend8_s $push[[NUM:[0-9]+]]=, $0{{$}}
 ; CHECK-NEXT: return $pop[[NUM]]{{$}}
 
-; NOATOMIC-LABEL: i32_extend8_s
-; NOATOMIC-NOT: i32.extend8_s
+; NOSIGNEXT-LABEL: i32_extend8_s
+; NOSIGNEXT-NOT: i32.extend8_s
 define i32 @i32_extend8_s(i8 %x) {
   %a = sext i8 %x to i32
   ret i32 %a
@@ -23,8 +23,8 @@ define i32 @i32_extend8_s(i8 %x) {
 ; CHECK-NEXT: i32.extend16_s $push[[NUM:[0-9]+]]=, $0{{$}}
 ; CHECK-NEXT: return $pop[[NUM]]{{$}}
 
-; NOATOMIC-LABEL: i32_extend16_s
-; NOATOMIC-NOT: i32.extend16_s
+; NOSIGNEXT-LABEL: i32_extend16_s
+; NOSIGNEXT-NOT: i32.extend16_s
 define i32 @i32_extend16_s(i16 %x) {
   %a = sext i16 %x to i32
   ret i32 %a
@@ -37,8 +37,8 @@ define i32 @i32_extend16_s(i16 %x) {
 ; CHECK-NEXT: i64.extend8_s $push[[NUM2:[0-9]+]]=, $pop[[NUM1]]{{$}}
 ; CHECK-NEXT: return $pop[[NUM2]]{{$}}
 
-; NOATOMIC-LABEL: i64_extend8_s
-; NOATOMIC-NOT: i64.extend8_s
+; NOSIGNEXT-LABEL: i64_extend8_s
+; NOSIGNEXT-NOT: i64.extend8_s
 define i64 @i64_extend8_s(i8 %x) {
   %a = sext i8 %x to i64
   ret i64 %a
@@ -51,8 +51,8 @@ define i64 @i64_extend8_s(i8 %x) {
 ; CHECK-NEXT: i64.extend16_s $push[[NUM2:[0-9]+]]=, $pop[[NUM1]]{{$}}
 ; CHECK-NEXT: return $pop[[NUM2]]{{$}}
 
-; NOATOMIC-LABEL: i64_extend16_s
-; NOATOMIC-NOT: i16.extend16_s
+; NOSIGNEXT-LABEL: i64_extend16_s
+; NOSIGNEXT-NOT: i16.extend16_s
 define i64 @i64_extend16_s(i16 %x) {
   %a = sext i16 %x to i64
   ret i64 %a