From: Chris Lattner <sabre@nondot.org>
Date: Thu, 14 Sep 2006 20:56:30 +0000 (+0000)
Subject: add a note
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=f0613e1e7cc8aae41350fb0b983ce5b43115b93a;p=oota-llvm.git

add a note


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30377 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt
index 2c99e02e4e2..b0840a5e501 100644
--- a/lib/Target/PowerPC/README.txt
+++ b/lib/Target/PowerPC/README.txt
@@ -539,3 +539,28 @@ be folded together.
 unsigned short G;
 void foo(unsigned long H) { G = H; }
 
+===-------------------------------------------------------------------------===
+
+We compile:
+
+unsigned test6(unsigned x) { 
+  return ((x & 0x00FF0000) >> 16) | ((x & 0x000000FF) << 16);
+}
+
+into:
+
+_test6:
+        lis r2, 255
+        rlwinm r3, r3, 16, 0, 31
+        ori r2, r2, 255
+        and r3, r3, r2
+        blr
+
+GCC gets it down to:
+
+_test6:
+        rlwinm r0,r3,16,8,15
+        rlwinm r3,r3,16,24,31
+        or r3,r3,r0
+        blr
+