From: Chris Lattner <sabre@nondot.org>
Date: Sun, 29 Jan 2006 09:08:15 +0000 (+0000)
Subject: add a missed optimization
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b638cd89dbe0f4a0a7ae51699efcb862f17355e8;p=oota-llvm.git

add a missed optimization


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25786 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index ac8f3f1e08f..0074eb43369 100644
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -204,3 +204,13 @@ There are two ways to fix this:
    disambiguate the pointers.
 
 Number 1 is the preferred solution.
+
+//===---------------------------------------------------------------------===//
+
+The instruction selector sometimes misses folding a load into a compare.  The
+pattern is written as (cmp reg, (load p)).  Because the compare isn't 
+commutative, it is not matched with the load on both sides.  The dag combiner
+should be made smart enough to cannonicalize the load into the RHS of a compare
+when it can invert the result of the compare for free.
+
+