Index: include/clang/Basic/BuiltinsWebAssembly.def
===================================================================
--- include/clang/Basic/BuiltinsWebAssembly.def
+++ include/clang/Basic/BuiltinsWebAssembly.def
@@ -56,4 +56,14 @@
 BUILTIN(__builtin_wasm_replace_lane_f32x4, "V4fV4fIif", "ncV:128:")
 BUILTIN(__builtin_wasm_replace_lane_f64x2, "V2dV2dIid", "ncV:128:")
 
+BUILTIN(__builtin_wasm_add_saturate_s_i8x16, "V16cV16cV16c", "ncV:128:")
+BUILTIN(__builtin_wasm_add_saturate_u_i8x16, "V16cV16cV16c", "ncV:128:")
+BUILTIN(__builtin_wasm_add_saturate_s_i16x8, "V8sV8sV8s", "ncV:128:")
+BUILTIN(__builtin_wasm_add_saturate_u_i16x8, "V8sV8sV8s", "ncV:128:")
+
+BUILTIN(__builtin_wasm_sub_saturate_s_i8x16, "V16cV16cV16c", "ncV:128:")
+BUILTIN(__builtin_wasm_sub_saturate_u_i8x16, "V16cV16cV16c", "ncV:128:")
+BUILTIN(__builtin_wasm_sub_saturate_s_i16x8, "V8sV8sV8s", "ncV:128:")
+BUILTIN(__builtin_wasm_sub_saturate_u_i16x8, "V8sV8sV8s", "ncV:128:")
+
 #undef BUILTIN
Index: lib/CodeGen/CGBuiltin.cpp
===================================================================
--- lib/CodeGen/CGBuiltin.cpp
+++ lib/CodeGen/CGBuiltin.cpp
@@ -12485,6 +12485,40 @@
       llvm_unreachable("unexpected builtin ID");
     }
   }
+  case WebAssembly::BI__builtin_wasm_add_saturate_s_i8x16:
+  case WebAssembly::BI__builtin_wasm_add_saturate_u_i8x16:
+  case WebAssembly::BI__builtin_wasm_add_saturate_s_i16x8:
+  case WebAssembly::BI__builtin_wasm_add_saturate_u_i16x8:
+  case WebAssembly::BI__builtin_wasm_sub_saturate_s_i8x16:
+  case WebAssembly::BI__builtin_wasm_sub_saturate_u_i8x16:
+  case WebAssembly::BI__builtin_wasm_sub_saturate_s_i16x8:
+  case WebAssembly::BI__builtin_wasm_sub_saturate_u_i16x8: {
+    unsigned IntNo;
+    switch (BuiltinID) {
+    case WebAssembly::BI__builtin_wasm_add_saturate_s_i8x16:
+    case WebAssembly::BI__builtin_wasm_add_saturate_s_i16x8:
+      IntNo = Intrinsic::wasm_add_saturate_signed;
+      break;
+    case WebAssembly::BI__builtin_wasm_add_saturate_u_i8x16:
+    case WebAssembly::BI__builtin_wasm_add_saturate_u_i16x8:
+      IntNo = Intrinsic::wasm_add_saturate_unsigned;
+      break;
+    case WebAssembly::BI__builtin_wasm_sub_saturate_s_i8x16:
+    case WebAssembly::BI__builtin_wasm_sub_saturate_s_i16x8:
+      IntNo = Intrinsic::wasm_sub_saturate_signed;
+      break;
+    case WebAssembly::BI__builtin_wasm_sub_saturate_u_i8x16:
+    case WebAssembly::BI__builtin_wasm_sub_saturate_u_i16x8:
+      IntNo = Intrinsic::wasm_sub_saturate_unsigned;
+      break;
+    default:
+      llvm_unreachable("unexpected builtin ID");
+    }
+    Value *LHS = EmitScalarExpr(E->getArg(0));
+    Value *RHS = EmitScalarExpr(E->getArg(1));
+    Value *Callee = CGM.getIntrinsic(IntNo, ConvertType(E->getType()));
+    return Builder.CreateCall(Callee, {LHS, RHS});
+  }
 
   default:
     return nullptr;
Index: test/CodeGen/builtins-wasm.c
===================================================================
--- test/CodeGen/builtins-wasm.c
+++ test/CodeGen/builtins-wasm.c
@@ -172,3 +172,59 @@
   // WEBASSEMBLY: insertelement <2 x double> %v, double %x, i32 1
   // WEBASSEMBLY-NEXT: ret
 }
+
+i8x16 f25(i8x16 x, i8x16 y) {
+  return __builtin_wasm_add_saturate_s_i8x16(x, y);
+  // WEBASSEMBLY: call <16 x i8> @llvm.wasm.add.saturate.signed.v16i8(
+  // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i8x16 f26(i8x16 x, i8x16 y) {
+  return __builtin_wasm_add_saturate_u_i8x16(x, y);
+  // WEBASSEMBLY: call <16 x i8> @llvm.wasm.add.saturate.unsigned.v16i8(
+  // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i16x8 f27(i16x8 x, i16x8 y) {
+  return __builtin_wasm_add_saturate_s_i16x8(x, y);
+  // WEBASSEMBLY: call <8 x i16> @llvm.wasm.add.saturate.signed.v8i16(
+  // WEBASSEMBLY-SAME: <8 x i16> %x, <8 x i16> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i16x8 f28(i16x8 x, i16x8 y) {
+  return __builtin_wasm_add_saturate_u_i16x8(x, y);
+  // WEBASSEMBLY: call <8 x i16> @llvm.wasm.add.saturate.unsigned.v8i16(
+  // WEBASSEMBLY-SAME: <8 x i16> %x, <8 x i16> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i8x16 f29(i8x16 x, i8x16 y) {
+  return __builtin_wasm_sub_saturate_s_i8x16(x, y);
+  // WEBASSEMBLY: call <16 x i8> @llvm.wasm.sub.saturate.signed.v16i8(
+  // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i8x16 f30(i8x16 x, i8x16 y) {
+  return __builtin_wasm_sub_saturate_u_i8x16(x, y);
+  // WEBASSEMBLY: call <16 x i8> @llvm.wasm.sub.saturate.unsigned.v16i8(
+  // WEBASSEMBLY-SAME: <16 x i8> %x, <16 x i8> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i16x8 f31(i16x8 x, i16x8 y) {
+  return __builtin_wasm_sub_saturate_s_i16x8(x, y);
+  // WEBASSEMBLY: call <8 x i16> @llvm.wasm.sub.saturate.signed.v8i16(
+  // WEBASSEMBLY-SAME: <8 x i16> %x, <8 x i16> %y)
+  // WEBASSEMBLY-NEXT: ret
+}
+
+i16x8 f32(i16x8 x, i16x8 y) {
+  return __builtin_wasm_sub_saturate_u_i16x8(x, y);
+  // WEBASSEMBLY: call <8 x i16> @llvm.wasm.sub.saturate.unsigned.v8i16(
+  // WEBASSEMBLY-SAME: <8 x i16> %x, <8 x i16> %y)
+  // WEBASSEMBLY-NEXT: ret
+}