[compiler] Remove Early/LateGraphTrimming phases

These don't improve codegen and are unecessary overhead.

BUG=v8:9684

Change-Id: I2feb1c1200eb0c347f4a21be5444b6a15924e6de
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2903162Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Ross McIlroy <rmcilroy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#74704}

src/compiler/pipeline.cc

@@ -1796,9 +1796,8 @@ struct EffectControlLinearizationPhase {
 
   void Run(PipelineData* data, Zone* temp_zone) {
     {
-      // The scheduler requires the graphs to be trimmed, so trim now.
-      // TODO(jarin) Remove the trimming once the scheduler can handle untrimmed
-      // graphs.
+      // Branch cloning in the effect control linearizer requires the graphs to
+      // be trimmed, so trim now before scheduling.
       GraphTrimmer trimmer(temp_zone, data->graph());
       NodeVector roots(temp_zone);
       data->jsgraph()->GetCachedNodes(&roots);
@@ -2087,34 +2086,6 @@ struct CsaOptimizationPhase {
   }
 };
 
-struct EarlyGraphTrimmingPhase {
-  DECL_PIPELINE_PHASE_CONSTANTS(EarlyTrimming)
-
-  void Run(PipelineData* data, Zone* temp_zone) {
-    GraphTrimmer trimmer(temp_zone, data->graph());
-    NodeVector roots(temp_zone);
-    data->jsgraph()->GetCachedNodes(&roots);
-    UnparkedScopeIfNeeded scope(data->broker(), FLAG_trace_turbo_trimming);
-    trimmer.TrimGraph(roots.begin(), roots.end());
-  }
-};
-
-
-struct LateGraphTrimmingPhase {
-  DECL_PIPELINE_PHASE_CONSTANTS(LateGraphTrimming)
-
-  void Run(PipelineData* data, Zone* temp_zone) {
-    GraphTrimmer trimmer(temp_zone, data->graph());
-    NodeVector roots(temp_zone);
-    if (data->jsgraph()) {
-      data->jsgraph()->GetCachedNodes(&roots);
-    }
-    UnparkedScopeIfNeeded scope(data->broker(), FLAG_trace_turbo_trimming);
-    trimmer.TrimGraph(roots.begin(), roots.end());
-  }
-};
-
-
 struct ComputeSchedulePhase {
   DECL_PIPELINE_PHASE_CONSTANTS(Scheduling)
 
@@ -2644,12 +2615,6 @@ bool PipelineImpl::CreateGraph() {
   Run<InliningPhase>();
   RunPrintAndVerify(InliningPhase::phase_name(), true);
 
-  // Remove dead->live edges from the graph.
-  if (!data->info()->IsTurboprop()) {
-    Run<EarlyGraphTrimmingPhase>();
-    RunPrintAndVerify(EarlyGraphTrimmingPhase::phase_name(), true);
-  }
-
   // Determine the Typer operation flags.
   {
     SharedFunctionInfoRef shared_info =
@@ -3412,11 +3377,6 @@ void PipelineImpl::ComputeScheduledGraph() {
   // We should only schedule the graph if it is not scheduled yet.
   DCHECK_NULL(data->schedule());
 
-  if (!data->info()->IsTurboprop()) {
-    Run<LateGraphTrimmingPhase>();
-    RunPrintAndVerify(LateGraphTrimmingPhase::phase_name(), true);
-  }
-
   Run<ComputeSchedulePhase>();
   TraceScheduleAndVerify(data->info(), data, data->schedule(), "schedule");
 }

src/logging/runtime-call-stats.h

@@ -334,7 +334,6 @@ class RuntimeCallTimer final {
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, DecideSpillingMode)              \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, DecompressionOptimization)       \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, EarlyOptimization)               \
-  ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, EarlyTrimming)                   \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, EffectLinearization)             \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, EscapeAnalysis)                  \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, FinalizeCode)                    \
@@ -346,7 +345,6 @@ class RuntimeCallTimer final {
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, MidTierRegisterAllocator)        \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, MidTierRegisterOutputDefinition) \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, MidTierSpillSlotAllocator)       \
-  ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, LateGraphTrimming)               \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, LateOptimization)                \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, LoadElimination)                 \
   ADD_THREAD_SPECIFIC_COUNTER(V, Optimize, LocateSpillSlots)                \