Reland "[ptr-compr] Storing a Tagged value stores the lower 32 bits"

This is a reland of 9b1e174f\

Reverted for a test failure that was unrelated to this CL. It was fixed in
https://chromium-review.googlesource.com/c/v8/v8/+/1845223.

Original change's description:
> [ptr-compr] Storing a Tagged value stores the lower 32 bits
>
> This CL changes the Tagged stores when pointer compression is enabled.
> It shouldn't affect anything for the time being since if we have pointer
> compression enabled, we are going to be storing Compressed values. Later,
> we will eliminate the Compressed representation and that it's where it
> will come into effect.
>
> The Arm64 side of the CL looks bigger since we eliminated the opcode in
> https://chromium-review.googlesource.com/c/v8/v8/+/1803345.
>
> Bug: v8:7703
> Change-Id: Ic4afbff9646b5d058adb9619b20ccccb3f5aed45
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1822044
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#64133}

Bug: v8:7703
Change-Id: I7775e90c36f180adb0484b22eaf3918d9c012b77
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1845219Reviewed-by: Igor Sheludko <ishell@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64156}

src/compiler/backend/arm64/code-generator-arm64.cc

@@ -1616,6 +1616,9 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
     case kArm64Str:
       __ Str(i.InputOrZeroRegister64(0), i.MemoryOperand(1));
       break;
+    case kArm64StrCompressTagged:
+      __ StoreTaggedField(i.InputOrZeroRegister64(0), i.MemoryOperand(1));
+      break;
     case kArm64DecompressSigned: {
       __ DecompressTaggedSigned(i.OutputRegister(), i.InputRegister(0));
       break;

src/compiler/backend/arm64/instruction-codes-arm64.h

@@ -164,6 +164,7 @@ namespace compiler {
   V(Arm64LdrDecompressTaggedPointer)        \
   V(Arm64LdrDecompressAnyTagged)            \
   V(Arm64Str)                               \
+  V(Arm64StrCompressTagged)                 \
   V(Arm64DecompressSigned)                  \
   V(Arm64DecompressPointer)                 \
   V(Arm64DecompressAny)                     \

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

@@ -355,6 +355,7 @@ int InstructionScheduler::GetTargetInstructionFlags(
     case kArm64Strh:
     case kArm64StrW:
     case kArm64Str:
+    case kArm64StrCompressTagged:
     case kArm64DmbIsh:
     case kArm64DsbIsb:
       return kHasSideEffect;

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

@@ -724,7 +724,7 @@ void InstructionSelector::VisitStore(Node* node) {
       case MachineRepresentation::kCompressedPointer:  // Fall through.
       case MachineRepresentation::kCompressed:
 #ifdef V8_COMPRESS_POINTERS
-        opcode = kArm64StrW;
+        opcode = kArm64StrCompressTagged;
         immediate_mode = kLoadStoreImm32;
         break;
 #else
@@ -732,7 +732,11 @@ void InstructionSelector::VisitStore(Node* node) {
 #endif
       case MachineRepresentation::kTaggedSigned:   // Fall through.
       case MachineRepresentation::kTaggedPointer:  // Fall through.
-      case MachineRepresentation::kTagged:         // Fall through.
+      case MachineRepresentation::kTagged:
+        opcode = kArm64StrCompressTagged;
+        immediate_mode =
+            COMPRESS_POINTERS_BOOL ? kLoadStoreImm32 : kLoadStoreImm64;
+        break;
       case MachineRepresentation::kWord64:
         opcode = kArm64Str;
         immediate_mode = kLoadStoreImm64;

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

@@ -288,7 +288,8 @@ ArchOpcode GetStoreOpcode(StoreRepresentation store_rep) {
 #endif
     case MachineRepresentation::kTaggedSigned:   // Fall through.
     case MachineRepresentation::kTaggedPointer:  // Fall through.
-    case MachineRepresentation::kTagged:         // Fall through.
+    case MachineRepresentation::kTagged:
+      return kX64MovqCompressTagged;
     case MachineRepresentation::kWord64:
       return kX64Movq;
     case MachineRepresentation::kSimd128:  // Fall through.