From a5c50baaf55fd415afdb8fd8a89d32370ab28a12 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Tue, 30 May 2006 21:29:15 +0000
Subject: [PATCH] Add a note

llvm-svn: 28572
---
 lib/Target/README.txt | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/lib/Target/README.txt b/lib/Target/README.txt
index 807768002b5..650eabf2d4d 100644
--- a/lib/Target/README.txt
+++ b/lib/Target/README.txt
@@ -251,3 +251,22 @@ void %test(uint* %P) {
         ret void
 }
 
+//===---------------------------------------------------------------------===//
+
+dag/inst combine "clz(x)>>5 -> x==0" for 32-bit x.
+
+Compile:
+
+int bar(int x)
+{
+  int t = __builtin_clz(x);
+  return -(t>>5);
+}
+
+to:
+
+_bar:   addic r3,r3,-1
+        subfe r3,r3,r3
+        blr
+
+