llvm/llvm/test/Analysis/BasicAA/noalias-bugs.ll

; RUN: opt -S -aa-pipeline=basic-aa -passes=dse < %s | FileCheck %s

target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; We incorrectly returned noalias in the example below for "ptr.64" and
; "either_ptr.64".
; PR18460

%nested = type { %nested.i64 }
%nested.i64 = type { i64 }

define i64 @testcase(ptr noalias %p1, ptr noalias %p2,
                     i32 %a, i32 %b) {
  %ptr = getelementptr inbounds %nested, ptr %p1, i64 -1, i32 0
  %ptr.64 = getelementptr inbounds %nested.i64, ptr %ptr, i64 0, i32 0
  %ptr2= getelementptr inbounds %nested, ptr %p2, i64 0, i32 0
  %cmp = icmp ult i32 %a, %b
  %either_ptr = select i1 %cmp, ptr %ptr2, ptr %ptr
  %either_ptr.64 = getelementptr inbounds %nested.i64, ptr %either_ptr, i64 0, i32 0

; Because either_ptr.64 and ptr.64 can alias (we used to return noalias)
; elimination of the first store is not valid.

; CHECK: store i64 2
; CHECK: load
; CHECK: store i64 1

  store i64 2, ptr %ptr.64, align 8
  %r = load i64, ptr %either_ptr.64, align 8
  store i64 1, ptr %ptr.64, align 8
  ret i64 %r
}