From 5f10c6820d9bbe50389b20cfc2bc2fe127e5b1b1 Mon Sep 17 00:00:00 2001
From: mvstanton <mvstanton@chromium.org>
Date: Fri, 3 Mar 2017 06:54:32 -0800
Subject: [PATCH] [Turbofan] Don't inline if we never saw a function.

Also prevent division by zero.

R=tebbi@chromium.org
BUG=

Review-Url: https://codereview.chromium.org/2731723002
Cr-Commit-Position: refs/heads/master@{#43590}
---
 src/compiler/js-inlining-heuristic.cc | 4 ++++
 src/feedback-vector.cc                | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/src/compiler/js-inlining-heuristic.cc b/src/compiler/js-inlining-heuristic.cc
index 6f99fbb183..59af71f1ae 100644
--- a/src/compiler/js-inlining-heuristic.cc
+++ b/src/compiler/js-inlining-heuristic.cc
@@ -164,6 +164,10 @@ void JSInliningHeuristic::Finalize() {
     auto i = candidates_.begin();
     Candidate candidate = *i;
     candidates_.erase(i);
+    // Only include candidates that we've successfully called before.
+    // The candidate list is sorted, so we can exit at the first occurance of
+    // frequency 0 in the list.
+    if (candidate.frequency <= 0.0) return;
     // Make sure we don't try to inline dead candidate nodes.
     if (!candidate.node->IsDead()) {
       Reduction const reduction = InlineCandidate(candidate);
diff --git a/src/feedback-vector.cc b/src/feedback-vector.cc
index 4003068e9b..5d84276399 100644
--- a/src/feedback-vector.cc
+++ b/src/feedback-vector.cc
@@ -591,6 +591,10 @@ int CallICNexus::ExtractCallCount() {
 float CallICNexus::ComputeCallFrequency() {
   double const invocation_count = vector()->invocation_count();
   double const call_count = ExtractCallCount();
+  if (invocation_count == 0) {
+    // Prevent division by 0.
+    return 0.0f;
+  }
   return static_cast<float>(call_count / invocation_count);
 }