[ia32] Optimize index calculation for certain checked load/stores.

src/compiler/ia32/instruction-selector-ia32.cc

 // Copyright 2014 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/base/adapters.h"
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 
 namespace v8 {
@@ skipping 377 matching lines @@
     case MachineRepresentation::kBit:            // Fall through.
     case MachineRepresentation::kTaggedSigned:   // Fall through.
     case MachineRepresentation::kTaggedPointer:  // Fall through.
     case MachineRepresentation::kTagged:         // Fall through.
     case MachineRepresentation::kWord64:         // Fall through.
     case MachineRepresentation::kSimd128:        // Fall through.
     case MachineRepresentation::kNone:
       UNREACHABLE();
       return;
   }
+  if (offset->opcode() == IrOpcode::kInt32Add && CanCover(node, offset)) {
+    Int32BinopMatcher moffset(offset);
+    InstructionOperand buffer_operand = g.CanBeImmediate(buffer)
+                                            ? g.UseImmediate(buffer)
+                                            : g.UseRegister(buffer);
+    Int32Matcher mlength(length);
+    if (mlength.HasValue() && moffset.right().HasValue() &&
+        moffset.right().Value() >= 0 &&
+        mlength.Value() >= moffset.right().Value()) {
+      Emit(opcode, g.DefineAsRegister(node),
+           g.UseImmediate(moffset.right().node()), g.UseImmediate(length),
+           g.UseRegister(moffset.left().node()), buffer_operand);
+      return;
+    }
+    IntMatcher<int32_t, IrOpcode::kRelocatableInt32Constant> mmlength(length);
+    if (mmlength.HasValue() && moffset.right().HasValue() &&
+        moffset.right().Value() >= 0 &&
+        mmlength.Value() >= moffset.right().Value()) {
+      Emit(opcode, g.DefineAsRegister(node),
+           g.UseImmediate(moffset.right().node()), g.UseImmediate(length),
+           g.UseRegister(moffset.left().node()), buffer_operand);
+      return;
+    }
+  }
   InstructionOperand offset_operand = g.UseRegister(offset);
   InstructionOperand length_operand =
       g.CanBeImmediate(length) ? g.UseImmediate(length) : g.UseRegister(length);
   if (g.CanBeImmediate(buffer)) {
     Emit(opcode | AddressingModeField::encode(kMode_MRI),
          g.DefineAsRegister(node), offset_operand, length_operand,
          offset_operand, g.UseImmediate(buffer));
   } else {
     Emit(opcode | AddressingModeField::encode(kMode_MR1),
          g.DefineAsRegister(node), offset_operand, length_operand,
@@ skipping 35 matching lines @@
     case MachineRepresentation::kNone:
       UNREACHABLE();
       return;
   }
   InstructionOperand value_operand =
       g.CanBeImmediate(value) ? g.UseImmediate(value)
                               : ((rep == MachineRepresentation::kWord8 ||
                                   rep == MachineRepresentation::kBit)
                                      ? g.UseByteRegister(value)
                                      : g.UseRegister(value));
+  if (offset->opcode() == IrOpcode::kInt32Add && CanCover(node, offset)) {
+    Int32BinopMatcher moffset(offset);
+    InstructionOperand buffer_operand = g.CanBeImmediate(buffer)
+                                            ? g.UseImmediate(buffer)
+                                            : g.UseRegister(buffer);
+    Int32Matcher mlength(length);
+    if (mlength.HasValue() && moffset.right().HasValue() &&
+        moffset.right().Value() >= 0 &&
+        mlength.Value() >= moffset.right().Value()) {
+      Emit(opcode, g.NoOutput(), g.UseImmediate(moffset.right().node()),
+           g.UseImmediate(length), value_operand,
+           g.UseRegister(moffset.left().node()), buffer_operand);
+      return;
+    }
+    IntMatcher<int32_t, IrOpcode::kRelocatableInt32Constant> mmlength(length);
+    if (mmlength.HasValue() && moffset.right().HasValue() &&
+        moffset.right().Value() >= 0 &&
+        mmlength.Value() >= moffset.right().Value()) {
+      Emit(opcode, g.NoOutput(), g.UseImmediate(moffset.right().node()),
+           g.UseImmediate(length), value_operand,
+           g.UseRegister(moffset.left().node()), buffer_operand);
+      return;
+    }
+  }
   InstructionOperand offset_operand = g.UseRegister(offset);
   InstructionOperand length_operand =
       g.CanBeImmediate(length) ? g.UseImmediate(length) : g.UseRegister(length);
   if (g.CanBeImmediate(buffer)) {
     Emit(opcode | AddressingModeField::encode(kMode_MRI), g.NoOutput(),
          offset_operand, length_operand, value_operand, offset_operand,
          g.UseImmediate(buffer));
   } else {
     Emit(opcode | AddressingModeField::encode(kMode_MR1), g.NoOutput(),
          offset_operand, length_operand, value_operand, g.UseRegister(buffer),
@@ skipping 1334 matching lines @@
 // static
 MachineOperatorBuilder::AlignmentRequirements
 InstructionSelector::AlignmentRequirements() {
   return MachineOperatorBuilder::AlignmentRequirements::
       FullUnalignedAccessSupport();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8