From 6e57b152283cbf1b4a9a75e9b1fb1b6d6eb5f6d6 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 6 Feb 2011 22:05:31 +0000
Subject: teach instsimplify to transform (X / Y) * Y to X when the div is an
 exact udiv.

llvm-svn: 124994
---
 llvm/test/Transforms/InstSimplify/reassociate.ll | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

(limited to 'llvm/test/Transforms')

diff --git a/llvm/test/Transforms/InstSimplify/reassociate.ll b/llvm/test/Transforms/InstSimplify/reassociate.ll
index 928442ac56c..3c8169e5e28 100644
--- a/llvm/test/Transforms/InstSimplify/reassociate.ll
+++ b/llvm/test/Transforms/InstSimplify/reassociate.ll
@@ -137,6 +137,7 @@ define i32 @sdiv5(i32 %x, i32 %y) {
 ; CHECK: ret i32 %x
 }
 
+
 define i32 @udiv1(i32 %x, i32 %y) {
 ; CHECK: @udiv1
 ; (no overflow X * Y) / Y -> X
@@ -164,3 +165,22 @@ define i32 @udiv3(i32 %x, i32 %y) {
   ret i32 %div
 ; CHECK: ret i32 0
 }
+
+define i32 @udiv4(i32 %x, i32 %y) {
+; CHECK: @udiv4
+; (X / Y) * Y -> X if the division is exact
+  %div = udiv exact i32 %x, %y
+  %mul = mul i32 %div, %y
+  ret i32 %mul
+; CHECK: ret i32 %x
+}
+
+define i32 @udiv5(i32 %x, i32 %y) {
+; CHECK: @udiv5
+; Y * (X / Y) -> X if the division is exact
+  %div = udiv exact i32 %x, %y
+  %mul = mul i32 %y, %div
+  ret i32 %mul
+; CHECK: ret i32 %x
+}
+
-- 
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