From 8963071a142368859fac215b68957a42286b3dd5 Mon Sep 17 00:00:00 2001 From: Arnold Schwaighofer Date: Thu, 16 Jan 2014 04:53:18 +0000 Subject: BasicAA: We need to check both access sizes when comparing a gep and an underlying object of unknown size. Fixes PR18460. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199351 91177308-0d34-0410-b5e6-96231b3b80d8 --- test/Analysis/BasicAA/noalias-bugs.ll | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) create mode 100644 test/Analysis/BasicAA/noalias-bugs.ll (limited to 'test/Analysis') diff --git a/test/Analysis/BasicAA/noalias-bugs.ll b/test/Analysis/BasicAA/noalias-bugs.ll new file mode 100644 index 0000000000..2bcc14fd93 --- /dev/null +++ b/test/Analysis/BasicAA/noalias-bugs.ll @@ -0,0 +1,33 @@ +; RUN: opt -S -basicaa -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(%nested * noalias %p1, %nested * noalias %p2, + i32 %a, i32 %b) { + %ptr = getelementptr inbounds %nested* %p1, i64 -1, i32 0 + %ptr.64 = getelementptr inbounds %nested.i64* %ptr, i64 0, i32 0 + %ptr2= getelementptr inbounds %nested* %p2, i64 0, i32 0 + %cmp = icmp ult i32 %a, %b + %either_ptr = select i1 %cmp, %nested.i64* %ptr2, %nested.i64* %ptr + %either_ptr.64 = getelementptr inbounds %nested.i64* %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, i64* %ptr.64, align 8 + %r = load i64* %either_ptr.64, align 8 + store i64 1, i64* %ptr.64, align 8 + ret i64 %r +} -- cgit v1.2.3