[WASM SIMD] Implement packing and unpacking integer conversions.

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index 62adc7a1473f4a3aba462634805a1727dad562da..4d187882763c338cece579a6e63ee6c8b08ceb1b 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -459,6 +459,8 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* I32x4ExtractLane(int32_t);
   const Operator* I32x4ReplaceLane(int32_t);
   const Operator* I32x4SConvertF32x4();
+  const Operator* I32x4SConvertI16x8Low();
+  const Operator* I32x4SConvertI16x8High();
   const Operator* I32x4Neg();
   const Operator* I32x4Shl(int32_t);
   const Operator* I32x4ShrS(int32_t);
@@ -473,6 +475,8 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* I32x4LeS();
 
   const Operator* I32x4UConvertF32x4();
+  const Operator* I32x4UConvertI16x8Low();
+  const Operator* I32x4UConvertI16x8High();
   const Operator* I32x4ShrU(int32_t);
   const Operator* I32x4MinU();
   const Operator* I32x4MaxU();
@@ -482,9 +486,12 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* I16x8Splat();
   const Operator* I16x8ExtractLane(int32_t);
   const Operator* I16x8ReplaceLane(int32_t);
+  const Operator* I16x8SConvertI8x16Low();
+  const Operator* I16x8SConvertI8x16High();
   const Operator* I16x8Neg();
   const Operator* I16x8Shl(int32_t);
   const Operator* I16x8ShrS(int32_t);
+  const Operator* I16x8SConvertI32x4();
   const Operator* I16x8Add();
   const Operator* I16x8AddSaturateS();
   const Operator* I16x8Sub();
@@ -497,7 +504,10 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* I16x8LtS();
   const Operator* I16x8LeS();
 
+  const Operator* I16x8UConvertI8x16Low();
+  const Operator* I16x8UConvertI8x16High();
   const Operator* I16x8ShrU(int32_t);
+  const Operator* I16x8UConvertI32x4();
   const Operator* I16x8AddSaturateU();
   const Operator* I16x8SubSaturateU();
   const Operator* I16x8MinU();
@@ -511,6 +521,7 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* I8x16Neg();
   const Operator* I8x16Shl(int32_t);
   const Operator* I8x16ShrS(int32_t);
+  const Operator* I8x16SConvertI16x8();
   const Operator* I8x16Add();
   const Operator* I8x16AddSaturateS();
   const Operator* I8x16Sub();
@@ -524,6 +535,7 @@ class V8_EXPORT_PRIVATE MachineOperatorBuilder final
   const Operator* I8x16LeS();
 
   const Operator* I8x16ShrU(int32_t);
+  const Operator* I8x16UConvertI16x8();
   const Operator* I8x16AddSaturateU();
   const Operator* I8x16SubSaturateU();
   const Operator* I8x16MinU();