[ptr-compr][codegen] Combine load and Any decompression when possible

Similar to https://chromium-review.googlesource.com/c/v8/v8/+/1697246 but
for the Any case.

Cq-Include-Trybots: luci.v8.try:v8_linux64_pointer_compression_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux64_arm64_pointer_compression_rel_ng
Bug: v8:7703
Change-Id: I99f839faad17da35adac8a084289b1553530d4a2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1698394Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62677}

src/compiler/backend/arm64/instruction-selector-arm64.cc

@@ -1646,7 +1646,17 @@ void InstructionSelector::VisitChangeTaggedSignedToCompressedSigned(
 void InstructionSelector::VisitChangeCompressedToTagged(Node* node) {
   Arm64OperandGenerator g(this);
   Node* const value = node->InputAt(0);
-  Emit(kArm64DecompressAny, g.DefineAsRegister(node), g.UseRegister(value));
+  if (value->opcode() == IrOpcode::kLoad && CanCover(node, value)) {
+    // TODO(v8:7703): Make this work with poisoned loads as well.
+    DCHECK_EQ(LoadRepresentationOf(value->op()).representation(),
+              MachineRepresentation::kCompressed);
+    InstructionCode opcode = kArm64LdrDecompressAnyTagged;
+    ImmediateMode immediate_mode = kLoadStoreImm32;
+    MachineRepresentation rep = MachineRepresentation::kCompressed;
+    EmitLoad(this, value, opcode, immediate_mode, rep, node);
+  } else {
+    Emit(kArm64DecompressAny, g.DefineAsRegister(node), g.UseRegister(value));
+  }
 }
 
 void InstructionSelector::VisitChangeCompressedPointerToTaggedPointer(

src/compiler/backend/x64/instruction-selector-x64.cc

@@ -1257,7 +1257,20 @@ void InstructionSelector::VisitChangeTaggedSignedToCompressedSigned(
 void InstructionSelector::VisitChangeCompressedToTagged(Node* node) {
   X64OperandGenerator g(this);
   Node* const value = node->InputAt(0);
-  Emit(kX64DecompressAny, g.DefineAsRegister(node), g.Use(value));
+  if (value->opcode() == IrOpcode::kLoad && CanCover(node, value)) {
+    DCHECK_EQ(LoadRepresentationOf(value->op()).representation(),
+              MachineRepresentation::kCompressed);
+    InstructionCode opcode = kX64MovqDecompressAnyTagged;
+    InstructionOperand outputs[] = {g.DefineAsRegister(node)};
+    size_t input_count = 0;
+    InstructionOperand inputs[3];
+    AddressingMode mode = g.GetEffectiveAddressMemoryOperand(
+        node->InputAt(0), inputs, &input_count);
+    opcode |= AddressingModeField::encode(mode);
+    Emit(opcode, 1, outputs, input_count, inputs);
+  } else {
+    Emit(kX64DecompressAny, g.DefineAsRegister(node), g.Use(value));
+  }
 }
 
 void InstructionSelector::VisitChangeCompressedPointerToTaggedPointer(