[wasm-simd] Remove the scalar lowering pass

Bug: v8:11613
Change-Id: Ica7fe5ca63fa3729614eb09ace26e679a88577ac
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2826728
Commit-Queue: Deepti Gandluri <gdeepti@chromium.org>
Reviewed-by: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74051}

BUILD.gn

@@ -2482,7 +2482,6 @@ v8_header_set("v8_internal_headers") {
     "src/compiler/select-lowering.h",
     "src/compiler/serializer-for-background-compilation.h",
     "src/compiler/serializer-hints.h",
-    "src/compiler/simd-scalar-lowering.h",
     "src/compiler/simplified-lowering.h",
     "src/compiler/simplified-operator-reducer.h",
     "src/compiler/simplified-operator.h",
@@ -3475,7 +3474,6 @@ v8_compiler_sources = [
 if (v8_enable_webassembly) {
   v8_compiler_sources += [
     "src/compiler/int64-lowering.cc",
-    "src/compiler/simd-scalar-lowering.cc",
     "src/compiler/wasm-compiler.cc",
   ]
 }

src/compiler/OWNERS

@@ -23,7 +23,3 @@ per-file opcodes.*=ahaas@chromium.org
 per-file opcodes.*=bbudge@chromium.org
 per-file opcodes.*=gdeepti@chromium.org
 per-file opcodes.*=zhin@chromium.org
-
-per-file simd-scalar-lowering.*=bbudge@chromium.org
-per-file simd-scalar-lowering.*=gdeepti@chromium.org
-per-file simd-scalar-lowering.*=zhin@chromium.org

src/compiler/simd-scalar-lowering.h

-// Copyright 2016 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.
-
-#ifndef V8_COMPILER_SIMD_SCALAR_LOWERING_H_
-#define V8_COMPILER_SIMD_SCALAR_LOWERING_H_
-
-#include "src/compiler/common-operator.h"
-#include "src/compiler/diamond.h"
-#include "src/compiler/graph.h"
-#include "src/compiler/machine-graph.h"
-#include "src/compiler/machine-operator.h"
-#include "src/compiler/node-marker.h"
-#include "src/compiler/simplified-operator.h"
-#include "src/zone/zone-containers.h"
-
-namespace v8 {
-namespace internal {
-
-template <typename T>
-class Signature;
-
-namespace compiler {
-
-class SimdScalarLowering {
- public:
-  SimdScalarLowering(MachineGraph* mcgraph,
-                     SimplifiedOperatorBuilder* simplified,
-                     Signature<MachineRepresentation>* signature);
-
-  void LowerGraph();
-
-  int GetParameterCountAfterLowering();
-
- private:
-  enum class State : uint8_t { kUnvisited, kOnStack, kVisited };
-
-  enum class SimdType : uint8_t {
-    kFloat64x2,
-    kFloat32x4,
-    kInt64x2,
-    kInt32x4,
-    kInt16x8,
-    kInt8x16
-  };
-
-#if defined(V8_TARGET_BIG_ENDIAN)
-  static constexpr int kLaneOffsets[16] = {15, 14, 13, 12, 11, 10, 9, 8,
-                                           7,  6,  5,  4,  3,  2,  1, 0};
-#else
-  static constexpr int kLaneOffsets[16] = {0, 1, 2,  3,  4,  5,  6,  7,
-                                           8, 9, 10, 11, 12, 13, 14, 15};
-#endif
-  struct Replacement {
-    Node** node = nullptr;
-    SimdType type;  // represents output type
-    int num_replacements = 0;
-  };
-
-  struct NodeState {
-    Node* node;
-    int input_index;
-  };
-
-  Zone* zone() const { return mcgraph_->zone(); }
-  Graph* graph() const { return mcgraph_->graph(); }
-  MachineOperatorBuilder* machine() const { return mcgraph_->machine(); }
-  CommonOperatorBuilder* common() const { return mcgraph_->common(); }
-  SimplifiedOperatorBuilder* simplified() const { return simplified_; }
-  Signature<MachineRepresentation>* signature() const { return signature_; }
-
-  void LowerNode(Node* node);
-  bool DefaultLowering(Node* node);
-
-  int NumLanes(SimdType type);
-  void ReplaceNode(Node* old, Node** new_nodes, int count);
-  bool HasReplacement(size_t index, Node* node);
-  Node** GetReplacements(Node* node);
-  int ReplacementCount(Node* node);
-  void Float64ToInt64(Node** replacements, Node** result);
-  void Float32ToInt32(Node** replacements, Node** result);
-  void Int32ToFloat32(Node** replacements, Node** result);
-  void Int64ToFloat64(Node** replacements, Node** result);
-  void Int64ToInt32(Node** replacements, Node** result);
-  template <typename T>
-  void Int32ToSmallerInt(Node** replacements, Node** result);
-  template <typename T>
-  void SmallerIntToInt32(Node** replacements, Node** result);
-  void Int32ToInt64(Node** replacements, Node** result);
-  Node** GetReplacementsWithType(Node* node, SimdType type);
-  SimdType ReplacementType(Node* node);
-  void PreparePhiReplacement(Node* phi);
-  void SetLoweredType(Node* node, Node* output);
-  void GetIndexNodes(Node* index, Node** new_indices, SimdType type);
-  void LowerLoadOp(Node* node, SimdType type);
-  void LowerLoadTransformOp(Node* node, SimdType type);
-  void LowerStoreOp(Node* node);
-  void LowerBinaryOp(Node* node, SimdType input_rep_type, const Operator* op,
-                     bool not_horizontal = true);
-  Node* ConstructPhiForComparison(Diamond d, SimdType rep_type, int true_value,
-                                  int false_value);
-  void LowerCompareOp(Node* node, SimdType input_rep_type, const Operator* op,
-                      bool invert_inputs = false);
-  Node* FixUpperBits(Node* input, int32_t shift);
-  void LowerBinaryOpForSmallInt(Node* node, SimdType input_rep_type,
-                                const Operator* op, bool not_horizontal = true);
-  Node* Mask(Node* input, int32_t mask);
-  void LowerSaturateBinaryOp(Node* node, SimdType input_rep_type,
-                             const Operator* op, bool is_signed);
-  void LowerUnaryOp(Node* node, SimdType input_rep_type, const Operator* op);
-  void LowerIntMinMax(Node* node, const Operator* op, bool is_max,
-                      SimdType type);
-  void LowerConvertFromFloat(Node* node, bool is_signed);
-  void LowerConvertFromInt(Node* node, SimdType input_rep_type,
-                           SimdType output_rep_type, bool is_signed,
-                           int start_index);
-  void LowerPack(Node* node, SimdType input_rep_type, SimdType output_rep_type,
-                 bool is_signed);
-  void LowerShiftOp(Node* node, SimdType type);
-  Node* BuildF64Trunc(Node* input);
-  void LowerNotEqual(Node* node, SimdType input_rep_type, const Operator* op);
-  MachineType MachineTypeFrom(SimdType simdType);
-  void LowerBitMaskOp(Node* node, SimdType rep_type, int msb_index);
-  void LowerAllTrueOp(Node* node, SimdType rep_type);
-  void LowerFloatPseudoMinMax(Node* node, const Operator* op, bool is_max,
-                              SimdType type);
-  void LowerExtMul(Node* node, const Operator* op, SimdType output_type,
-                   SimdType input_type, bool low, bool is_signed);
-
-  // Extends node, which is a lowered node of type rep_type, e.g. int8, int16,
-  // int32 to a 32-bit or 64-bit node. node should be a lowered node (i.e. not a
-  // SIMD node). The assumption here is that small ints are stored sign
-  // extended.
-  Node* ExtendNode(Node* node, SimdType rep_type, bool is_signed);
-
-  MachineGraph* const mcgraph_;
-  SimplifiedOperatorBuilder* const simplified_;
-  NodeMarker<State> state_;
-  ZoneDeque<NodeState> stack_;
-  Replacement* replacements_;
-  Signature<MachineRepresentation>* signature_;
-  Node* placeholder_;
-  int parameter_count_after_lowering_;
-};
-
-}  // namespace compiler
-}  // namespace internal
-}  // namespace v8
-
-#endif  // V8_COMPILER_SIMD_SCALAR_LOWERING_H_

src/compiler/wasm-compiler.cc

@@ -34,7 +34,6 @@
 #include "src/compiler/node-origin-table.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/pipeline.h"
-#include "src/compiler/simd-scalar-lowering.h"
 #include "src/compiler/zone-stats.h"
 #include "src/execution/isolate-inl.h"
 #include "src/heap/factory.h"
@@ -7795,49 +7794,8 @@ bool BuildGraphForWasmFunction(AccountingAllocator* allocator,
     return false;
   }
 
-  // Lower SIMD first, i64x2 nodes will be lowered to int64 nodes, then int64
-  // lowering will take care of them.
   auto sig = CreateMachineSignature(mcgraph->zone(), func_body.sig,
                                     WasmGraphBuilder::kCalledFromWasm);
-  if (builder.has_simd() &&
-      (!CpuFeatures::SupportsWasmSimd128() || env->lower_simd)) {
-    SimplifiedOperatorBuilder simplified(mcgraph->zone());
-    SimdScalarLowering(mcgraph, &simplified, sig).LowerGraph();
-
-    // SimdScalarLowering changes all v128 to 4 i32, so update the machine
-    // signature for the call to LowerInt64.
-    size_t return_count = 0;
-    size_t param_count = 0;
-    for (auto ret : sig->returns()) {
-      return_count += ret == MachineRepresentation::kSimd128 ? 4 : 1;
-    }
-    for (auto param : sig->parameters()) {
-      param_count += param == MachineRepresentation::kSimd128 ? 4 : 1;
-    }
-
-    Signature<MachineRepresentation>::Builder sig_builder(
-        mcgraph->zone(), return_count, param_count);
-    for (auto ret : sig->returns()) {
-      if (ret == MachineRepresentation::kSimd128) {
-        for (int i = 0; i < 4; ++i) {
-          sig_builder.AddReturn(MachineRepresentation::kWord32);
-        }
-      } else {
-        sig_builder.AddReturn(ret);
-      }
-    }
-    for (auto param : sig->parameters()) {
-      if (param == MachineRepresentation::kSimd128) {
-        for (int i = 0; i < 4; ++i) {
-          sig_builder.AddParam(MachineRepresentation::kWord32);
-        }
-      } else {
-        sig_builder.AddParam(param);
-      }
-    }
-    sig = sig_builder.Build();
-  }
-
   builder.LowerInt64(sig);
 
   if (func_index >= FLAG_trace_wasm_ast_start &&

test/cctest/BUILD.gn

@@ -439,7 +439,6 @@ v8_source_set("cctest_sources") {
       "wasm/test-run-wasm-relaxed-simd.cc",
       "wasm/test-run-wasm-sign-extension.cc",
       "wasm/test-run-wasm-simd-liftoff.cc",
-      "wasm/test-run-wasm-simd-scalar-lowering.cc",
       "wasm/test-run-wasm-simd.cc",
       "wasm/test-run-wasm-wrappers.cc",
       "wasm/test-run-wasm.cc",

test/cctest/cctest.status

@@ -384,7 +384,6 @@
 
   # SIMD not fully implemented yet
   'test-run-wasm-simd-liftoff/*': [SKIP],
-  'test-run-wasm-simd-scalar-lowering/*':[SKIP],
   'test-run-wasm-simd/*':[SKIP],
 
   # Some wasm functionality is not implemented yet
@@ -700,7 +699,6 @@
 ['no_simd_sse == True', {
   'test-run-wasm-simd/*': [SKIP],
   'test-run-wasm-simd-liftoff/*': [SKIP],
-  'test-run-wasm-simd-scalar-lowering/*': [SKIP],
 }],  # no_simd_sse == True
 
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