[WebAssembly] Saturating arithmetic intrinsics

[tlively]

Summary

Depends on D52805.

[tlively]

• Add newline for readability.

[aheejin]

lib/Target/WebAssembly/WebAssemblyISelLowering.cpp

993

Newline here? :3

[tlively]

• Another newline

[tlively]

• Rebase

[aheejin]

test/CodeGen/WebAssembly/simd-arith.ll

6

Do we need both the slow and fast versions for NO-SIMD128 too? Aren't they the same anyway?

[tlively]

• Remove unused FileCheck labels

[aheejin]

test/CodeGen/WebAssembly/simd-arith.ll

6

Oh what I meant is... do we need to test both with and without fastisel for NO-SIMD128? With NO-SIMD128 we are just testing the pre-existing scalar expansion behavior and checking the SIMD instructions do not kick in.

[tlively]

test/CodeGen/WebAssembly/simd-arith.ll

6

Sounds like fast isel is responsible for complying with architecture features itself, so we still need this test.

include/llvm/IR/IntrinsicsWebAssembly.td

def int_wasm_atomic_notify:
   Intrinsic<[llvm_i32_ty], [LLVMPointerType<llvm_i32_ty>, llvm_i32_ty],
             [IntrInaccessibleMemOnly, NoCapture<0>, IntrHasSideEffects], "",
             [SDNPMemOperand]>;
 
 //===----------------------------------------------------------------------===//
 // SIMD intrinsics
 //===----------------------------------------------------------------------===//
 
+def int_wasm_add_saturate_signed :
+  Intrinsic<[llvm_anyvector_ty],
+            [LLVMMatchType<0>, LLVMMatchType<0>],
+            [IntrNoMem, IntrSpeculatable]>;
+def int_wasm_add_saturate_unsigned :
+  Intrinsic<[llvm_anyvector_ty],
+            [LLVMMatchType<0>, LLVMMatchType<0>],
+            [IntrNoMem, IntrSpeculatable]>;
+def int_wasm_sub_saturate_signed :
+  Intrinsic<[llvm_anyvector_ty],
+            [LLVMMatchType<0>, LLVMMatchType<0>],
+            [IntrNoMem, IntrSpeculatable]>;
+def int_wasm_sub_saturate_unsigned :
+  Intrinsic<[llvm_anyvector_ty],
+            [LLVMMatchType<0>, LLVMMatchType<0>],
+            [IntrNoMem, IntrSpeculatable]>;
 def int_wasm_bitselect :
   Intrinsic<[llvm_anyvector_ty],
             [LLVMMatchType<0>, LLVMMatchType<0>, LLVMMatchType<0>],
             [IntrNoMem, IntrSpeculatable]>;
 def int_wasm_anytrue :
   Intrinsic<[llvm_i32_ty],
             [llvm_anyvector_ty],
             [IntrNoMem, IntrSpeculatable]>;
 def int_wasm_alltrue :
   Intrinsic<[llvm_i32_ty],
             [llvm_anyvector_ty],
             [IntrNoMem, IntrSpeculatable]>;
 
 } // TargetPrefix = "wasm"

lib/Target/WebAssembly/WebAssemblyISD.def

 HANDLE_NODETYPE(ARGUMENT)
 HANDLE_NODETYPE(Wrapper)
 HANDLE_NODETYPE(BR_IF)
 HANDLE_NODETYPE(BR_TABLE)
 HANDLE_NODETYPE(SHUFFLE)
 HANDLE_NODETYPE(ANYTRUE)
 HANDLE_NODETYPE(ALLTRUE)
 HANDLE_NODETYPE(BITSELECT)
+HANDLE_NODETYPE(ADD_SAT_S)
+HANDLE_NODETYPE(ADD_SAT_U)
+HANDLE_NODETYPE(SUB_SAT_S)
+HANDLE_NODETYPE(SUB_SAT_U)
 
 // add memory opcodes starting at ISD::FIRST_TARGET_MEMORY_OPCODE here...

lib/Target/WebAssembly/WebAssemblyISelLowering.cpp

 WebAssemblyTargetLowering::LowerINTRINSIC_WO_CHAIN(SDValue Op,
                                                    SelectionDAG &DAG) const {
   unsigned IntNo = cast<ConstantSDNode>(Op.getOperand(0))->getZExtValue();
   SDLoc DL(Op);
   switch (IntNo) {
   default:
     return {}; // Don't custom lower most intrinsics.
 
+  case Intrinsic::wasm_add_saturate_signed:
+  case Intrinsic::wasm_add_saturate_unsigned:
+  case Intrinsic::wasm_sub_saturate_signed:
+  case Intrinsic::wasm_sub_saturate_unsigned: {
+    unsigned OpCode;
+    switch (IntNo) {
+    case Intrinsic::wasm_add_saturate_signed:
+      OpCode = WebAssemblyISD::ADD_SAT_S;
+      break;
+    case Intrinsic::wasm_add_saturate_unsigned:
+      OpCode = WebAssemblyISD::ADD_SAT_U;
+      break;
+    case Intrinsic::wasm_sub_saturate_signed:
+      OpCode = WebAssemblyISD::SUB_SAT_S;
+      break;
+    case Intrinsic::wasm_sub_saturate_unsigned:
+      OpCode = WebAssemblyISD::SUB_SAT_U;
+      break;
+    default:
+      llvm_unreachable("unexpected intrinsic id");
+      break;
+    }
+    return DAG.getNode(OpCode, DL, Op.getValueType(), Op.getOperand(1),
+                       Op.getOperand(2));
+  }
+
   case Intrinsic::wasm_bitselect:
     return DAG.getNode(WebAssemblyISD::BITSELECT, DL, Op.getValueType(),
                        Op.getOperand(1), Op.getOperand(2), Op.getOperand(3));
 
   case Intrinsic::wasm_anytrue:
   case Intrinsic::wasm_alltrue: {
     unsigned OpCode = IntNo == Intrinsic::wasm_anytrue
                           ? WebAssemblyISD::ANYTRUE

lib/Target/WebAssembly/WebAssemblyInstrSIMD.td

 // constrained immediate argument types
 foreach SIZE = [8, 16] in
 def ImmI#SIZE : ImmLeaf<i32, "return (Imm & ((1UL << "#SIZE#") - 1)) == Imm;">;
 foreach SIZE = [2, 4, 8, 16, 32] in
 def LaneIdx#SIZE : ImmLeaf<i32, "return 0 <= Imm && Imm < "#SIZE#";">;
 
 // Custom nodes for custom operations
 def wasm_shuffle_t : SDTypeProfile<1, 18, []>;
+def wasm_saturate_t : SDTypeProfile<1, 2,
+  [SDTCisVec<0>, SDTCisSameAs<0, 1>, SDTCisSameAs<0, 2>]
+>;
 def wasm_bitselect_t : SDTypeProfile<1, 3,
   [SDTCisVec<0>, SDTCisSameAs<0, 1>, SDTCisSameAs<0, 2>, SDTCisSameAs<0, 3>]
 >;
 def wasm_reduce_t : SDTypeProfile<1, 1, [SDTCisVT<0, i32>, SDTCisVec<1>]>;
 def wasm_shuffle : SDNode<"WebAssemblyISD::SHUFFLE", wasm_shuffle_t>;
+def wasm_add_sat_s : SDNode<"WebAssemblyISD::ADD_SAT_S", wasm_saturate_t>;
+def wasm_add_sat_u : SDNode<"WebAssemblyISD::ADD_SAT_U", wasm_saturate_t>;
+def wasm_sub_sat_s : SDNode<"WebAssemblyISD::SUB_SAT_S", wasm_saturate_t>;
+def wasm_sub_sat_u : SDNode<"WebAssemblyISD::SUB_SAT_U", wasm_saturate_t>;
 def wasm_bitselect : SDNode<"WebAssemblyISD::BITSELECT", wasm_bitselect_t>;
 def wasm_anytrue : SDNode<"WebAssemblyISD::ANYTRUE", wasm_reduce_t>;
 def wasm_alltrue : SDNode<"WebAssemblyISD::ALLTRUE", wasm_reduce_t>;
 
 multiclass ConstVec<ValueType vec_t, dag ops, dag pat, string args> {
   let isMoveImm = 1, isReMaterializable = 1 in
   defm CONST_V128_#vec_t : SIMD_I<(outs V128:$dst), ops, (outs), ops,
                                   [(set V128:$dst, (vec_t pat))],

 multiclass SIMDBinaryInt<SDNode node, string name, bits<32> baseInst> {
   defm "" : SIMDBinaryIntNoI64x2<node, name, baseInst>;
   defm "" : SIMDBinary<v2i64, "i64x2", node, name, !add(baseInst, 3)>;
 }
 multiclass SIMDBinaryFP<SDNode node, string name, bits<32> baseInst> {
   defm "" : SIMDBinary<v4f32, "f32x4", node, name, baseInst>;
   defm "" : SIMDBinary<v2f64, "f64x2", node, name, !add(baseInst, 1)>;
 }
+multiclass SIMDBinarySat<SDNode node, string name, bits<32> baseInst> {
+  defm "" : SIMDBinary<v16i8, "i8x16", node, name, baseInst>;
+  defm "" : SIMDBinary<v8i16, "i16x8", node, name, !add(baseInst, 2)>;
+}
 multiclass SIMDShift<ValueType vec_t, string vec, SDNode node, dag shift_vec,
                      string name, bits<32> simdop> {
   defm _#vec_t : SIMD_I<(outs V128:$dst), (ins V128:$vec, I32:$x),
                         (outs), (ins),
                         [(set (vec_t V128:$dst),
                           (node V128:$vec, (vec_t shift_vec)))],
                         vec#"."#name#"\t$dst, $vec, $x", vec#"."#name, simdop>;
 }
SIMD_I<(outs V128:$dst),
            "$m8, $m9, $mA, $mB, $mC, $mD, $mE, $mF",
          23>;
 
 let isCommutable = 1 in {
 defm ADD : SIMDBinaryInt<add, "add", 24>;
 defm ADD : SIMDBinaryFP<fadd, "add", 133>;
 defm MUL : SIMDBinaryIntNoI64x2<mul, "mul", 32>;
 defm MUL : SIMDBinaryFP<fmul, "mul", 139>;
+defm ADD_SAT_S : SIMDBinarySat<wasm_add_sat_s, "add_saturate_s", 40>;
+defm ADD_SAT_U : SIMDBinarySat<wasm_add_sat_u, "add_saturate_u", 41>;
 } // isCommutable = 1
 
 defm SUB : SIMDBinaryInt<sub, "sub", 28>;
 defm SUB : SIMDBinaryFP<fsub, "sub", 135>;
+defm SUB_SAT_S : SIMDBinarySat<wasm_sub_sat_s, "sub_saturate_s", 44>;
+defm SUB_SAT_U : SIMDBinarySat<wasm_sub_sat_u, "sub_saturate_u", 45>;
 defm DIV : SIMDBinaryFP<fdiv, "div", 137>;
 
 defm "" : SIMDNegInt<v16i8, "i8x16", splat16, i32, 36>;
 defm "" : SIMDNegInt<v8i16, "i16x8", splat8, i32, 37>;
 defm "" : SIMDNegInt<v4i32, "i32x4", splat4, i32, 38>;
 defm "" : SIMDNegInt<v2i64, "i64x2", splat2, i64, 39>;
 defm "" : SIMDNegFP<v4f32, "f32x4", splat4, f32, 125>;
 defm "" : SIMDNegFP<v2f64, "f64x2", splat2, f64, 126>;

test/CodeGen/WebAssembly/simd-arith.ll

 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -wasm-enable-unimplemented-simd -mattr=+simd128 | FileCheck %s --check-prefixes CHECK,SIMD128,SIMD128-SLOW
 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -wasm-enable-unimplemented-simd -mattr=+simd128 -fast-isel | FileCheck %s --check-prefixes CHECK,SIMD128,SIMD128-FAST
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+simd128 | FileCheck %s --check-prefixes CHECK,SIMD128-VM,SIMD128-VM-SLOW
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+simd128 -fast-isel | FileCheck %s --check-prefixes CHECK,SIMD128-VM,SIMD128-VM-FAST
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=-simd128 | FileCheck %s --check-prefixes CHECK,NO-SIMD128,NO-SIMD128-SLOW
-; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=-simd128 -fast-isel | FileCheck %s --check-prefixes CHECK,NO-SIMD128,NO-SIMD128-FAST
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+simd128 | FileCheck %s --check-prefixes CHECK,SIMD128-VM
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=+simd128 -fast-isel | FileCheck %s --check-prefixes CHECK,SIMD128-VM
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=-simd128 | FileCheck %s --check-prefixes CHECK,NO-SIMD128
+; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -mattr=-simd128 -fast-isel | FileCheck %s --check-prefixes CHECK,NO-SIMD128
 
 ; Test that basic SIMD128 arithmetic operations assemble as expected.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
 ; ==============================================================================
 ; 16 x i8

test/CodeGen/WebAssembly/simd-intrinsics.ll

 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -wasm-enable-unimplemented-simd -mattr=+simd128 | FileCheck %s --check-prefixes CHECK,SIMD128
 ; RUN: llc < %s -asm-verbose=false -disable-wasm-fallthrough-return-opt -wasm-disable-explicit-locals -wasm-keep-registers -wasm-enable-unimplemented-simd -mattr=+simd128 -fast-isel | FileCheck %s --check-prefixes CHECK,SIMD128
 
 ; Test that SIMD128 intrinsics lower as expected. These intrinsics are
 ; only expected to lower successfully if the simd128 attribute is
 ; enabled and legal types are used.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
 ; ==============================================================================
 ; 16 x i8
 ; ==============================================================================
+; CHECK-LABEL: add_sat_s_v16i8:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i8x16.add_saturate_s $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <16 x i8> @llvm.wasm.add.saturate.signed.v16i8(<16 x i8>, <16 x i8>)
+define <16 x i8> @add_sat_s_v16i8(<16 x i8> %x, <16 x i8> %y) {
+  %a = call <16 x i8> @llvm.wasm.add.saturate.signed.v16i8(
+    <16 x i8> %x, <16 x i8> %y
+  )
+  ret <16 x i8> %a
+}
+
+; CHECK-LABEL: add_sat_u_v16i8:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i8x16.add_saturate_u $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <16 x i8> @llvm.wasm.add.saturate.unsigned.v16i8(<16 x i8>, <16 x i8>)
+define <16 x i8> @add_sat_u_v16i8(<16 x i8> %x, <16 x i8> %y) {
+  %a = call <16 x i8> @llvm.wasm.add.saturate.unsigned.v16i8(
+    <16 x i8> %x, <16 x i8> %y
+  )
+  ret <16 x i8> %a
+}
+
+; CHECK-LABEL: sub_sat_s_v16i8:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i8x16.sub_saturate_s $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <16 x i8> @llvm.wasm.sub.saturate.signed.v16i8(<16 x i8>, <16 x i8>)
+define <16 x i8> @sub_sat_s_v16i8(<16 x i8> %x, <16 x i8> %y) {
+  %a = call <16 x i8> @llvm.wasm.sub.saturate.signed.v16i8(
+    <16 x i8> %x, <16 x i8> %y
+  )
+  ret <16 x i8> %a
+}
+
+; CHECK-LABEL: sub_sat_u_v16i8:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i8x16.sub_saturate_u $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <16 x i8> @llvm.wasm.sub.saturate.unsigned.v16i8(<16 x i8>, <16 x i8>)
+define <16 x i8> @sub_sat_u_v16i8(<16 x i8> %x, <16 x i8> %y) {
+  %a = call <16 x i8> @llvm.wasm.sub.saturate.unsigned.v16i8(
+    <16 x i8> %x, <16 x i8> %y
+  )
+  ret <16 x i8> %a
+}
+
 ; CHECK-LABEL: any_v16i8:
 ; SIMD128-NEXT: .param v128{{$}}
 ; SIMD128-NEXT: .result i32{{$}}
 ; SIMD128-NEXT: i8x16.any_true $push[[R:[0-9]+]]=, $0{{$}}
 ; SIMD128-NEXT: return $pop[[R]]{{$}}
 declare i32 @llvm.wasm.anytrue.v16i8(<16 x i8>)
 define i32 @any_v16i8(<16 x i8> %x) {
   %a = call i32 @llvm.wasm.anytrue.v16i8(<16 x i8> %x)
%a = call <16 x i8> @llvm.wasm.bitselect.v16i8(
     <16 x i8> %c, <16 x i8> %v1, <16 x i8> %v2
   )
   ret <16 x i8> %a
 }
 
 ; ==============================================================================
 ; 8 x i16
 ; ==============================================================================
+; CHECK-LABEL: add_sat_s_v8i16:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i16x8.add_saturate_s $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <8 x i16> @llvm.wasm.add.saturate.signed.v8i16(<8 x i16>, <8 x i16>)
+define <8 x i16> @add_sat_s_v8i16(<8 x i16> %x, <8 x i16> %y) {
+  %a = call <8 x i16> @llvm.wasm.add.saturate.signed.v8i16(
+    <8 x i16> %x, <8 x i16> %y
+  )
+  ret <8 x i16> %a
+}
+
+; CHECK-LABEL: add_sat_u_v8i16:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i16x8.add_saturate_u $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <8 x i16> @llvm.wasm.add.saturate.unsigned.v8i16(<8 x i16>, <8 x i16>)
+define <8 x i16> @add_sat_u_v8i16(<8 x i16> %x, <8 x i16> %y) {
+  %a = call <8 x i16> @llvm.wasm.add.saturate.unsigned.v8i16(
+    <8 x i16> %x, <8 x i16> %y
+  )
+  ret <8 x i16> %a
+}
+
+; CHECK-LABEL: sub_sat_s_v8i16:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i16x8.sub_saturate_s $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <8 x i16> @llvm.wasm.sub.saturate.signed.v8i16(<8 x i16>, <8 x i16>)
+define <8 x i16> @sub_sat_s_v8i16(<8 x i16> %x, <8 x i16> %y) {
+  %a = call <8 x i16> @llvm.wasm.sub.saturate.signed.v8i16(
+    <8 x i16> %x, <8 x i16> %y
+  )
+  ret <8 x i16> %a
+}
+
+; CHECK-LABEL: sub_sat_u_v8i16:
+; SIMD128-NEXT: .param v128, v128{{$}}
+; SIMD128-NEXT: .result v128{{$}}
+; SIMD128-NEXT: i16x8.sub_saturate_u $push[[R:[0-9]+]]=, $0, $1{{$}}
+; SIMD128-NEXT: return $pop[[R]]{{$}}
+declare <8 x i16> @llvm.wasm.sub.saturate.unsigned.v8i16(<8 x i16>, <8 x i16>)
+define <8 x i16> @sub_sat_u_v8i16(<8 x i16> %x, <8 x i16> %y) {
+  %a = call <8 x i16> @llvm.wasm.sub.saturate.unsigned.v8i16(
+    <8 x i16> %x, <8 x i16> %y
+  )
+  ret <8 x i16> %a
+}
+
 ; CHECK-LABEL: any_v8i16:
 ; SIMD128-NEXT: .param v128{{$}}
 ; SIMD128-NEXT: .result i32{{$}}
 ; SIMD128-NEXT: i16x8.any_true $push[[R:[0-9]+]]=, $0{{$}}
 ; SIMD128-NEXT: return $pop[[R]]{{$}}
 declare i32 @llvm.wasm.anytrue.v8i16(<8 x i16>)
 define i32 @any_v8i16(<8 x i16> %x) {
   %a = call i32 @llvm.wasm.anytrue.v8i16(<8 x i16> %x)

test/MC/WebAssembly/simd-encodings.s

# RUN: llvm-mc -show-encoding -triple=wasm32-unkown-unknown -mattr=+sign-ext,+simd128 < %s | FileCheck %s
     i16x8.neg
 
     # CHECK: i32x4.neg # encoding: [0xfd,0x26]
     i32x4.neg
 
     # CHECK: i64x2.neg # encoding: [0xfd,0x27]
     i64x2.neg
 
+    # CHECK: i8x16.add_saturate_s # encoding: [0xfd,0x28]
+    i8x16.add_saturate_s
+
+    # CHECK: i8x16.add_saturate_u # encoding: [0xfd,0x29]
+    i8x16.add_saturate_u
+
+    # CHECK: i16x8.add_saturate_s # encoding: [0xfd,0x2a]
+    i16x8.add_saturate_s
+
+    # CHECK: i16x8.add_saturate_u # encoding: [0xfd,0x2b]
+    i16x8.add_saturate_u
+
+    # CHECK: i8x16.sub_saturate_s # encoding: [0xfd,0x2c]
+    i8x16.sub_saturate_s
+
+    # CHECK: i8x16.sub_saturate_u # encoding: [0xfd,0x2d]
+    i8x16.sub_saturate_u
+
+    # CHECK: i16x8.sub_saturate_s # encoding: [0xfd,0x2e]
+    i16x8.sub_saturate_s
+
+    # CHECK: i16x8.sub_saturate_u # encoding: [0xfd,0x2f]
+    i16x8.sub_saturate_u
+
     # CHECK: i8x16.shl # encoding: [0xfd,0x30]
     i8x16.shl
 
     # CHECK: i16x8.shl # encoding: [0xfd,0x31]
     i16x8.shl
 
     # CHECK: i32x4.shl # encoding: [0xfd,0x32]
     i32x4.shl