[ptr-compr][CSA] Enabling the DecompressionElimination AdvancedReducer

Also adding a pair of valid compress/decompress that was missing.

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: v8:8977, v8:7703, chromium:963759
Change-Id: I668c26e636996e1c7621a23743df33b73e18ae89
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1624787
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61816}

src/compiler/decompression-elimination.cc

@@ -35,7 +35,8 @@ bool DecompressionElimination::IsValidDecompress(
       return IrOpcode::IsDecompressOpcode(decompressOpcode);
     case IrOpcode::kChangeTaggedSignedToCompressedSigned:
       return decompressOpcode ==
-             IrOpcode::kChangeCompressedSignedToTaggedSigned;
+                 IrOpcode::kChangeCompressedSignedToTaggedSigned ||
+             decompressOpcode == IrOpcode::kChangeCompressedToTagged;
     case IrOpcode::kChangeTaggedPointerToCompressedPointer:
       return decompressOpcode ==
                  IrOpcode::kChangeCompressedPointerToTaggedPointer ||

src/compiler/pipeline.cc

@@ -1593,6 +1593,11 @@ struct CsaOptimizationPhase {
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->broker(), data->common(),
                                          data->machine(), temp_zone);
+#ifdef V8_COMPRESS_POINTERS
+    DecompressionElimination decompression_elimination(
+        &graph_reducer, data->graph(), data->machine(), data->common());
+    AddReducer(data, &graph_reducer, &decompression_elimination);
+#endif
     AddReducer(data, &graph_reducer, &branch_condition_elimination);
     AddReducer(data, &graph_reducer, &dead_code_elimination);
     AddReducer(data, &graph_reducer, &machine_reducer);