From 7ba4e17285ba271758dc478cf422b64e7a2f0e8e Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 4 Jan 2010 18:38:39 +0000
Subject: [PATCH] Add a comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92492 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/VMCore/Instruction.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index 170a15f216f..3fabfd07b31 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -399,6 +399,8 @@ bool Instruction::isSafeToSpeculativelyExecute() const {
   case Load: {
     if (cast<LoadInst>(this)->isVolatile())
       return false;
+    // Note that it is not safe to speculate into a malloc'd region because
+    // malloc may return null.
     if (isa<AllocaInst>(getOperand(0)))
       return true;
     if (GlobalVariable *GV = dyn_cast<GlobalVariable>(getOperand(0)))