diff test/Analysis/BasicAA/2003-02-26-AccessSizeTest.ll @ 0:95c75e76d11b LLVM3.4

LLVM 3.4
author Kaito Tokumori <e105711@ie.u-ryukyu.ac.jp>
date Thu, 12 Dec 2013 13:56:28 +0900
parents
children afa8332a0e37
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/Analysis/BasicAA/2003-02-26-AccessSizeTest.ll	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,20 @@
+; This testcase makes sure that size is taken to account when alias analysis 
+; is performed.  It is not legal to delete the second load instruction because
+; the value computed by the first load instruction is changed by the store.
+
+; RUN: opt < %s -basicaa -gvn -instcombine -S | FileCheck %s
+
+define i32 @test() {
+; CHECK: %Y.DONOTREMOVE = load i32* %A
+; CHECK: %Z = sub i32 0, %Y.DONOTREMOVE
+  %A = alloca i32
+  store i32 0, i32* %A
+  %X = load i32* %A
+  %B = bitcast i32* %A to i8*
+  %C = getelementptr i8* %B, i64 1
+  store i8 1, i8* %C    ; Aliases %A
+  %Y.DONOTREMOVE = load i32* %A
+  %Z = sub i32 %X, %Y.DONOTREMOVE
+  ret i32 %Z
+}
+