[compiler] Add the DecompressionOptimization phase to TurboProp

The DecompressionOptimizationPhase performs MachineRepresentation
changes in the nodes, which causes the node's instruction selection
to avoid decompression.

It is safe to run after we already have a schedule since it does not
drop any nodes.

Bug: v8:9684, v8:7703
Change-Id: I636ae80fa82d0c78878756e9f39e7a14c02803b0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2324252
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Reviewed-by: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69137}

src/compiler/pipeline.cc

@@ -2678,6 +2678,11 @@ bool PipelineImpl::OptimizeGraphForMidTier(Linkage* linkage) {
   Run<ScheduledMachineLoweringPhase>();
   RunPrintAndVerify(ScheduledMachineLoweringPhase::phase_name(), true);
 
+  // The DecompressionOptimizationPhase updates node's operations but does not
+  // otherwise rewrite the graph, thus it is safe to run on a scheduled graph.
+  Run<DecompressionOptimizationPhase>();
+  RunPrintAndVerify(DecompressionOptimizationPhase::phase_name(), true);
+
   data->source_positions()->RemoveDecorator();
   if (data->info()->trace_turbo_json()) {
     data->node_origins()->RemoveDecorator();