From b727960f786225dec877f9a12f4aeeb45d7aaace Mon Sep 17 00:00:00 2001
From: Devang Patel <dpatel@apple.com>
Date: Wed, 19 Mar 2008 23:05:52 +0000
Subject: [PATCH] Add comment.

llvm-svn: 48567
---
 llvm/lib/Transforms/Scalar/LoopUnroll.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/llvm/lib/Transforms/Scalar/LoopUnroll.cpp b/llvm/lib/Transforms/Scalar/LoopUnroll.cpp
index 71a5955b76b0..1962c14d5d6c 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnroll.cpp
@@ -101,6 +101,10 @@ static unsigned ApproximateLoopSize(const Loop *L) {
       } else if (isa<DbgInfoIntrinsic>(I)) {
         // Ignore debug instructions
       } else if (isa<CallInst>(I)) {
+        // Estimate size overhead introduced by call instructions which
+        // is higher than other instructions. Here 3 and 10 are magic
+        // numbers that help one isolated test case from PR2067 without
+        // negatively impacting measured benchmarks.
         if (isa<IntrinsicInst>(I))
           Size = Size + 3;
         else