From 6c3fc0a52d75b9792c85ba88c4d6d30d568455db Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 1 Jan 2011 22:57:31 +0000
Subject: [PATCH] a missed __builtin_object_size case.

llvm-svn: 122676
---
 llvm/lib/Target/README.txt | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/llvm/lib/Target/README.txt b/llvm/lib/Target/README.txt
index be0e6bb82e44..4e374e59d6db 100644
--- a/llvm/lib/Target/README.txt
+++ b/llvm/lib/Target/README.txt
@@ -2074,3 +2074,20 @@ define i1 @g(i32 a) nounwind readnone {
 }
 
 //===---------------------------------------------------------------------===//
+
+This code can be seen in viterbi:
+
+  %64 = call noalias i8* @malloc(i64 %62) nounwind
+...
+  %67 = call i64 @llvm.objectsize.i64(i8* %64, i1 false) nounwind
+  %68 = call i8* @__memset_chk(i8* %64, i32 0, i64 %62, i64 %67) nounwind
+
+llvm.objectsize.i64 should be taught about malloc/calloc, allowing it to
+fold to %62.  This is a security win (overflows of malloc will get caught)
+and also a performance win by exposing more memsets to the optimizer.
+
+This occurs several times in viterbi.
+
+//===---------------------------------------------------------------------===//
+
+