[turbofan] Don't try to inling dead nodes.

src/compiler/js-inlining-heuristic.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-inlining-heuristic.h"
 
 #include "src/compiler.h"
 #include "src/compiler/node-matchers.h"
 #include "src/objects-inl.h"
 
@@ skipping 89 matching lines @@
 
   // We inline at most one candidate in every iteration of the fixpoint.
   // This is to ensure that we don't consume the full inlining budget
   // on things that aren't called very often.
   // TODO(bmeurer): Use std::priority_queue instead of std::set here.
   while (!candidates_.empty()) {
     if (cumulative_count_ > FLAG_max_inlined_nodes_cumulative) return;
     auto i = candidates_.begin();
     Candidate candidate = *i;
     candidates_.erase(i);
-    Reduction r = inliner_.ReduceJSCall(candidate.node, candidate.function);
-    if (r.Changed()) {
-      cumulative_count_ += candidate.function->shared()->ast_node_count();
-      return;
+    // Make sure we don't try to inline dead candidate nodes.

[Michael Starzinger, 2015/12/07 10:50:49]

suggestion: Could also be phrased as "if (candidate.node->IsDead()) continue",
might be more readable, but not sure, up to you.

[Benedikt Meurer, 2015/12/07 11:25:44]

Had that initially, but changed it to this.

+    if (!candidate.node->IsDead()) {
+      Reduction r = inliner_.ReduceJSCall(candidate.node, candidate.function);
+      if (r.Changed()) {
+        cumulative_count_ += candidate.function->shared()->ast_node_count();
+        return;
+      }
     }
   }
 }
 
 
 bool JSInliningHeuristic::CandidateCompare::operator()(
     const Candidate& left, const Candidate& right) const {
   return left.node != right.node && left.calls >= right.calls;
 }
 
 
 void JSInliningHeuristic::PrintCandidates() {
   PrintF("Candidates for inlining (size=%zu):\n", candidates_.size());
   for (const Candidate& candidate : candidates_) {
     PrintF("  id:%d, calls:%d, size[source]:%d, size[ast]:%d / %s\n",
            candidate.node->id(), candidate.calls,
            candidate.function->shared()->SourceSize(),
            candidate.function->shared()->ast_node_count(),
            candidate.function->shared()->DebugName()->ToCString().get());
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8