[ptr-compr][Turbofan] Adding missing representation changes corner cases

TaggedSigned to CompressedPointer, and TaggedPointer to CompressedSigned.

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: I9a257e583527256230576c7bc3d4c4b308570d2f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1585729
Auto-Submit: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61046}

src/compiler/representation-change.cc

@@ -592,7 +592,7 @@ Node* RepresentationChanger::GetCompressedSignedRepresentationFor(
         node);
   } else if (output_rep == MachineRepresentation::kTaggedSigned) {
     op = machine()->ChangeTaggedSignedToCompressedSigned();
-  } else if (output_rep == MachineRepresentation::kTagged) {
+  } else if (CanBeTaggedPointer(output_rep)) {
     if (use_info.type_check() == TypeCheckKind::kSignedSmall) {
       op = simplified()->CheckedTaggedToCompressedSigned(use_info.feedback());
     } else if (output_type.Is(Type::SignedSmall())) {
@@ -642,7 +642,7 @@ Node* RepresentationChanger::GetCompressedPointerRepresentationFor(
         node);
   } else if (output_rep == MachineRepresentation::kTaggedPointer) {
     op = machine()->ChangeTaggedPointerToCompressedPointer();
-  } else if (output_rep == MachineRepresentation::kTagged &&
+  } else if (CanBeTaggedSigned(output_rep) &&
              use_info.type_check() == TypeCheckKind::kHeapObject) {
     if (!output_type.Maybe(Type::SignedSmall())) {
       return node;
@@ -650,8 +650,6 @@ Node* RepresentationChanger::GetCompressedPointerRepresentationFor(
     // TODO(turbofan): Consider adding a Bailout operator that just deopts
     // for TaggedSigned output representation.
     op = simplified()->CheckedTaggedToCompressedPointer(use_info.feedback());
-    return TypeError(node, output_rep, output_type,
-                     MachineRepresentation::kCompressedPointer);
   } else if (output_rep == MachineRepresentation::kBit) {
     // TODO(v8:8977): specialize here and below
     node = GetTaggedPointerRepresentationFor(node, output_rep, output_type,

test/cctest/compiler/test-representation-change.cc

@@ -663,6 +663,18 @@ TEST(CompressedAndTagged) {
   CheckChange(IrOpcode::kChangeTaggedToCompressedSigned,
               MachineRepresentation::kTagged, Type::SignedSmall(),
               MachineRepresentation::kCompressedSigned);
+
+  // TaggedSigned to CompressedPointer
+  CheckChange(IrOpcode::kCheckedTaggedToCompressedPointer,
+              MachineRepresentation::kTaggedSigned, Type::SignedSmall(),
+              UseInfo(MachineRepresentation::kCompressedPointer,
+                      Truncation::Any(), TypeCheckKind::kHeapObject));
+
+  // CompressedSigned to TaggedPointer
+  CheckChange(IrOpcode::kCheckedCompressedToTaggedPointer,
+              MachineRepresentation::kCompressedSigned, Type::SignedSmall(),
+              UseInfo(MachineRepresentation::kTaggedPointer, Truncation::Any(),
+                      TypeCheckKind::kHeapObject));
 }
 
 static void TestMinusZeroCheck(IrOpcode::Value expected, Type from_type) {