diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
--- a/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td
@@ -1165,7 +1165,11 @@
   OutPatFrag<(ops node:$val),
              (EXTRACT_LANE_I64x2
                (NARROW_U_I8x16
-                 (AND (SPLAT_I32x4 (CONST_I32 0x00ff00ff)), node:$val),
+                 (AND
+                   (CONST_V128_I16x8
+                     0x00ff, 0x00ff, 0x00ff, 0x00ff,
+                     0x00ff, 0x00ff, 0x00ff, 0x00ff),
+                   node:$val),
                  $val), // Unused input
                0)>;
 
@@ -1173,7 +1177,10 @@
   OutPatFrag<(ops node:$val),
              (EXTRACT_LANE_I64x2
                (NARROW_U_I16x8
-                 (AND (SPLAT_I32x4 (CONST_I32 0x0000ffff)), node:$val),
+                 (AND
+                  (CONST_V128_I32x4
+                    0x0000ffff, 0x0000ffff, 0x0000ffff, 0x0000ffff),
+                  node:$val),
                  $val), // Unused input
                0)>;
 
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
--- a/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyRegStackify.cpp
@@ -121,14 +121,9 @@
         Type::getDoubleTy(MF.getFunction().getContext())));
     MI->addOperand(MachineOperand::CreateFPImm(Val));
   } else if (RegClass == &WebAssembly::V128RegClass) {
-    // TODO: Replace this with v128.const 0 once that is supported in V8
-    Register TempReg = MRI.createVirtualRegister(&WebAssembly::I32RegClass);
-    MI->setDesc(TII->get(WebAssembly::SPLAT_I32x4));
-    MI->addOperand(MachineOperand::CreateReg(TempReg, false));
-    MachineInstr *Const = BuildMI(*MI->getParent(), MI, MI->getDebugLoc(),
-                                  TII->get(WebAssembly::CONST_I32), TempReg)
-                              .addImm(0);
-    LIS.InsertMachineInstrInMaps(*Const);
+    MI->setDesc(TII->get(WebAssembly::CONST_V128_I64x2));
+    MI->addOperand(MachineOperand::CreateImm(0));
+    MI->addOperand(MachineOperand::CreateImm(0));
   } else {
     llvm_unreachable("Unexpected reg class");
   }
diff --git a/llvm/test/CodeGen/WebAssembly/implicit-def.ll b/llvm/test/CodeGen/WebAssembly/implicit-def.ll
--- a/llvm/test/CodeGen/WebAssembly/implicit-def.ll
+++ b/llvm/test/CodeGen/WebAssembly/implicit-def.ll
@@ -97,10 +97,7 @@
 }
 
 ; CHECK-LABEL: implicit_def_v4i32:
-; CHECK:      i32.const $push{{[0-9]+}}=, 0{{$}}
-; CHECK:      i32.const $push{{[0-9]+}}=, 0{{$}}
-; CHECK:      i32.const $push[[L0:[0-9]+]]=, 0{{$}}
-; CHECK-NEXT: i32x4.splat $push[[R:[0-9]+]]=, $pop[[L0]]
+; CHECK:      v128.const $push[[R:[0-9]+]]=, 0, 0{{$}}
 ; CHECK-NEXT: return $pop[[R]]{{$}}
 define <4 x i32> @implicit_def_v4i32() {
   br i1 undef, label %A, label %X
diff --git a/llvm/test/CodeGen/WebAssembly/simd-offset.ll b/llvm/test/CodeGen/WebAssembly/simd-offset.ll
--- a/llvm/test/CodeGen/WebAssembly/simd-offset.ll
+++ b/llvm/test/CodeGen/WebAssembly/simd-offset.ll
@@ -923,8 +923,7 @@
 ; CHECK:         .functype store_narrowing_v8i16 (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    local.get 1
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -956,8 +955,7 @@
 ; CHECK:         .functype store_narrowing_v8i16_with_folded_offset (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    local.get 1
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -990,8 +988,7 @@
 ; CHECK:         .functype store_narrowing_v8i16_with_folded_gep_offset (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    local.get 1
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1026,8 +1023,7 @@
 ; CHECK-NEXT:    local.get 1
 ; CHECK-NEXT:    i32.const -8
 ; CHECK-NEXT:    i32.add
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1064,8 +1060,7 @@
 ; CHECK-NEXT:    local.get 1
 ; CHECK-NEXT:    i32.const 16
 ; CHECK-NEXT:    i32.add
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1102,8 +1097,7 @@
 ; CHECK-NEXT:    local.get 1
 ; CHECK-NEXT:    i32.const 8
 ; CHECK-NEXT:    i32.add
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1134,8 +1128,7 @@
 ; CHECK:         .functype store_narrowing_v8i16_to_numeric_address (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    i32.const 0
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1165,8 +1158,7 @@
 ; CHECK:         .functype store_narrowing_v8i16_to_global_address (v128) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    i32.const 0
-; CHECK-NEXT:    i32.const 16711935
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 255, 255, 255, 255, 255, 255, 255, 255
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1753,8 +1745,7 @@
 ; CHECK:         .functype store_narrowing_v4i32 (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    local.get 1
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1786,8 +1777,7 @@
 ; CHECK:         .functype store_narrowing_v4i32_with_folded_offset (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    local.get 1
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1820,8 +1810,7 @@
 ; CHECK:         .functype store_narrowing_v4i32_with_folded_gep_offset (v128, i32) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    local.get 1
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1856,8 +1845,7 @@
 ; CHECK-NEXT:    local.get 1
 ; CHECK-NEXT:    i32.const -8
 ; CHECK-NEXT:    i32.add
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1894,8 +1882,7 @@
 ; CHECK-NEXT:    local.get 1
 ; CHECK-NEXT:    i32.const 16
 ; CHECK-NEXT:    i32.add
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1932,8 +1919,7 @@
 ; CHECK-NEXT:    local.get 1
 ; CHECK-NEXT:    i32.const 8
 ; CHECK-NEXT:    i32.add
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1964,8 +1950,7 @@
 ; CHECK:         .functype store_narrowing_v4i32_to_numeric_address (v128) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    i32.const 0
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0
@@ -1995,8 +1980,7 @@
 ; CHECK:         .functype store_narrowing_v4i32_to_global_address (v128) -> ()
 ; CHECK-NEXT:  # %bb.0:
 ; CHECK-NEXT:    i32.const 0
-; CHECK-NEXT:    i32.const 65535
-; CHECK-NEXT:    i32x4.splat
+; CHECK-NEXT:    v128.const 65535, 65535, 65535, 65535
 ; CHECK-NEXT:    local.get 0
 ; CHECK-NEXT:    v128.and
 ; CHECK-NEXT:    local.get 0