Revert "[turbofan] trim effect chain nodes when they have no side-effect"

tebbi · Commit Bot · commit 92d8e450ecb9 · 2018-01-24T12:42:37.000Z
This reverts commit e02f561. Reason for revert: Regresses compile time: chromium:803840 Original change's description: > [turbofan] trim effect chain nodes when they have no side-effect > > Bug: > Change-Id: Ic1b6dc6fcd8bfc4f0c3dbb101a38106aa3596a12 > Reviewed-on: https://chromium-review.googlesource.com/863886 > Commit-Queue: Tobias Tebbi <tebbi@chromium.org> > Reviewed-by: Jaroslav Sevcik <jarin@chromium.org> > Cr-Commit-Position: refs/heads/master@{#50588} TBR=jarin@chromium.org,tebbi@chromium.org Change-Id: I631840ca3b79272108d5696e6dc68d671774e35c Bug: Reviewed-on: https://chromium-review.googlesource.com/883521 Commit-Queue: Tobias Tebbi <tebbi@chromium.org> Reviewed-by: Tobias Tebbi <tebbi@chromium.org> Cr-Commit-Position: refs/heads/master@{#50833}
diff --git a/src/compiler/graph-trimmer.cc b/src/compiler/graph-trimmer.cc
@@ -5,7 +5,6 @@
 #include "src/compiler/graph-trimmer.h"
 
 #include "src/compiler/graph.h"
-#include "src/compiler/node-properties.h"
 
 namespace v8 {
 namespace internal {
@@ -19,64 +18,15 @@ GraphTrimmer::GraphTrimmer(Zone* zone, Graph* graph)
 
 GraphTrimmer::~GraphTrimmer() {}
 
-namespace {
-bool IsSideEffectFree(const Operator* op) {
-  switch (op->opcode()) {
-    case IrOpcode::kLoad:
-    case IrOpcode::kLoadElement:
-    case IrOpcode::kLoadField:
-    case IrOpcode::kTypeGuard:
-      return true;
-    default:
-      return false;
-  }
-}
-}  // namespace
 
 void GraphTrimmer::TrimGraph() {
   // Mark end node as live.
   MarkAsLive(graph()->end());
   // Compute transitive closure of live nodes.
   for (size_t i = 0; i < live_.size(); ++i) {
     Node* const live = live_[i];
-    for (Edge edge : live->input_edges()) {
-      Node* input = edge.to();
-      if (NodeProperties::IsEffectEdge(edge)) {
-        while (IsSideEffectFree(input->op())) {
-          // Side-effect free effect chain nodes can be removed from the effect
-          // chain when only their effect output is used. So we ignore the
-          // effect chain use when determining liveness.
-          DCHECK_EQ(1, input->op()->EffectInputCount());
-          input = NodeProperties::GetEffectInput(input);
-        }
-      }
-      MarkAsLive(input);
-    }
+    for (Node* const input : live->inputs()) MarkAsLive(input);
   }
-
-  // Remove unused side-effect-free nodes from the effect chain.
-  // These are exactly the nodes we skipped before and that don't have value
-  // uses. This has to be done before we remove dead->live edges because we need
-  // to read the effect predecessor from the dead effect chain node.
-  for (Node* const live : live_) {
-    DCHECK(IsLive(live));
-    for (Edge edge : live->input_edges()) {
-      Node* input = edge.to();
-      if (NodeProperties::IsEffectEdge(edge)) {
-        Node* new_input = input;
-        while (!IsLive(new_input)) {
-          DCHECK(IsSideEffectFree(new_input->op()));
-          if (FLAG_trace_turbo_trimming) {
-            OFStream os(stdout);
-            os << "DeadEffectChainNode: " << *new_input << std::endl;
-          }
-          new_input = NodeProperties::GetEffectInput(new_input);
-        }
-        if (new_input != input) edge.UpdateTo(new_input);
-      }
-    }
-  }
-
   // Remove dead->live edges.
   for (Node* const live : live_) {
     DCHECK(IsLive(live));
