From af50f816d24cef5ff639db48722851c48e43b058 Mon Sep 17 00:00:00 2001
From: Pat Gavlin <pagavlin@microsoft.com>
Date: Tue, 25 Jul 2017 17:39:21 -0700
Subject: [PATCH] Set `BBF_RUN_RARELY` for a scratch first BB if called count
 is 0.

Just what it says on the tin.

Fixes VSO 469624.
---
 src/jit/flowgraph.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/jit/flowgraph.cpp b/src/jit/flowgraph.cpp
index 5dab6bb..0c8a28e 100644
--- a/src/jit/flowgraph.cpp
+++ b/src/jit/flowgraph.cpp
@@ -12836,6 +12836,10 @@ void Compiler::fgComputeEdgeWeights()
         if (fgFirstBBisScratch())
         {
             fgFirstBB->setBBProfileWeight(fgCalledCount);
+            if (fgFirstBB->bbWeight == 0)
+            {
+                fgFirstBB->bbFlags |= BBF_RUN_RARELY;
+            }
         }
 
 #if DEBUG
-- 
2.7.4