From f14d33d4cb1ebbbe5cfe0071b1e2ae50a15a9890 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Sat, 4 Jun 2011 07:05:05 +0000
Subject: [PATCH] Add a testcase to demonstrate the problem where phi
 translation is ignored for clobbering partial-alias loads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132633 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../GVN/phi-translate-partial-alias.ll        | 27 +++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 test/Transforms/GVN/phi-translate-partial-alias.ll

diff --git a/test/Transforms/GVN/phi-translate-partial-alias.ll b/test/Transforms/GVN/phi-translate-partial-alias.ll
new file mode 100644
index 00000000000..47bec41fb16
--- /dev/null
+++ b/test/Transforms/GVN/phi-translate-partial-alias.ll
@@ -0,0 +1,27 @@
+; RUN: opt -basicaa -gvn -S < %s | FileCheck %s
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-f128:128:128-n8:16:32:64"
+
+; GVN shouldn't PRE the load around the loop backedge because it's
+; not actually redundant around the loop backedge, despite appearances
+; if phi-translation is ignored.
+
+; CHECK: define void @test0(i8* %begin)
+; CHECK: loop:
+; CHECK:   %l0 = load i8* %phi
+; CHECK:   call void @bar(i8 %l0)
+; CHECK:   %l1 = load i8* %phi
+define void @test0(i8* %begin) {
+entry:
+  br label %loop
+
+loop:
+  %phi = phi i8* [ %begin, %entry ], [ %next, %loop ]
+  %l0 = load i8* %phi
+  call void @bar(i8 %l0)
+  %l1 = load i8* %phi
+  %next = getelementptr inbounds i8* %phi, i8 %l1
+  br label %loop
+}
+
+declare void @bar(i8)