[wasm] Implement I32x4ReplaceLane, I32x4Add, I32x4Sub.

src/wasm/ast-decoder.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/signature.h"
 
 #include "src/bit-vector.h"
 #include "src/flags.h"
 #include "src/handles.h"
 #include "src/zone/zone-containers.h"
@@ skipping 1227 matching lines @@
   int DecodeStoreMem(LocalType type, MachineType mem_type) {
     MemoryAccessOperand operand(this, pc_,
                                 ElementSizeLog2Of(mem_type.representation()));
     Value val = Pop(1, type);
     Value index = Pop(0, kAstI32);
     BUILD(StoreMem, mem_type, index.node, operand.offset, operand.alignment,
           val.node, position());
     return 1 + operand.length;
   }
 
+  uint8_t LaneValue(uint8_t max_lanes) {

[titzer, 2016/10/07 12:20:14]

Maybe you should introduce a LaneOperand, since if we eventually do implement
this in the interpreter, we can use it there, too?

[gdeepti, 2016/11/22 01:15:20]

LaneOperand introduced by ScalarLowering, merged to use here as well. 

+    uint8_t lane = this->checked_read_u8(pc_, 2, "lane number");
+    if (lane < 0 || lane > (max_lanes - 1)) {
+      error(pc_, pc_ + 2, "invalid Simd128 lane value");
+    }
+    return lane;
+  }
+
   unsigned DecodeSimdOpcode(WasmOpcode opcode) {
     unsigned len = 0;
+    static const int kInt32x4MaxLanes = 4;
     switch (opcode) {
+      case kExprI32x4ReplaceLane: {
+        compiler::NodeVector inputs(3, zone_);
+        inputs[2] = Pop(1, LocalType::kWord32).node;
+        inputs[1] = builder_->Int32Constant(LaneValue(kInt32x4MaxLanes));
+        inputs[0] = Pop(0, LocalType::kSimd128).node;
+        TFNode* node = BUILD(SimdOp, opcode, inputs);
+        Push(LocalType::kSimd128, node);
+        len++;
+        break;
+      }
       case kExprI32x4ExtractLane: {
-        uint8_t lane = this->checked_read_u8(pc_, 2, "lane number");
-        if (lane < 0 || lane > 3) {
-          error(pc_, pc_ + 2, "invalid extract lane value");
-        }
-        TFNode* input = Pop(0, LocalType::kSimd128).node;
-        TFNode* node = BUILD(SimdExtractLane, opcode, lane, input);
+        compiler::NodeVector inputs(2, zone_);
+        inputs[1] = builder_->Int32Constant(LaneValue(kInt32x4MaxLanes));
+        inputs[0] = Pop(0, LocalType::kSimd128).node;
+        TFNode* node = BUILD(SimdOp, opcode, inputs);
         Push(LocalType::kWord32, node);
         len++;
         break;
       }
       default: {
         FunctionSig* sig = WasmOpcodes::Signature(opcode);
         if (sig != nullptr) {
           compiler::NodeVector inputs(sig->parameter_count(), zone_);
           for (size_t i = sig->parameter_count(); i > 0; i--) {
             Value val = Pop(static_cast<int>(i - 1), sig->GetParam(i - 1));
@@ skipping 665 matching lines @@
 BitVector* AnalyzeLoopAssignmentForTesting(Zone* zone, size_t num_locals,
                                            const byte* start, const byte* end) {
   FunctionBody body = {nullptr, nullptr, nullptr, start, end};
   WasmFullDecoder decoder(zone, nullptr, body);
   return decoder.AnalyzeLoopAssignmentForTesting(start, num_locals);
 }
 
 }  // namespace wasm
 }  // namespace internal
 }  // namespace v8