From: Chris Lattner <sabre@nondot.org>
Date: Tue, 30 May 2006 21:29:15 +0000 (+0000)
Subject: Add a note
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=9e18ef52625dbcd33e0f415cea8cead2966a9f9b;p=oota-llvm.git

Add a note


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28572 91177308-0d34-0410-b5e6-96231b3b80d8
---

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
+
+