From: Chris Lattner <sabre@nondot.org>
Date: Sun, 24 Jan 2010 02:27:03 +0000 (+0000)
Subject: move PR5945 here.
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3f6bfdaedaca984c178f1668c1ca08f52d607aee;p=oota-llvm.git

move PR5945 here.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94350 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/PowerPC/README.txt b/lib/Target/PowerPC/README.txt
index 5af108ac683..8f265cfc488 100644
--- a/lib/Target/PowerPC/README.txt
+++ b/lib/Target/PowerPC/README.txt
@@ -430,6 +430,35 @@ This theoretically may help improve twolf slightly (used in dimbox.c:142?).
 
 ===-------------------------------------------------------------------------===
 
+PR5945: This: 
+define i32 @clamp0g(i32 %a) {
+entry:
+        %cmp = icmp slt i32 %a, 0
+        %sel = select i1 %cmp, i32 0, i32 %a
+        ret i32 %sel
+}
+
+Is compile to this with the PowerPC (32-bit) backend:
+
+_clamp0g:
+        cmpwi cr0, r3, 0
+        li r2, 0
+        blt cr0, LBB1_2
+; BB#1:                                                     ; %entry
+        mr r2, r3
+LBB1_2:                                                     ; %entry
+        mr r3, r2
+        blr
+
+This could be reduced to the much simpler:
+
+_clamp0g:
+        srawi r2, r3, 31
+        andc r3, r3, r2
+        blr
+
+===-------------------------------------------------------------------------===
+
 int foo(int N, int ***W, int **TK, int X) {
   int t, i;