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| author | David Majnemer <david.majnemer@gmail.com> | 2013-11-07 22:15:53 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2013-11-07 22:15:53 +0000 |
| commit | 0ab20588523b59a65a4a29d47184a41443fa9337 (patch) | |
| tree | e497851cb16eb365bdce1806199408264e48388f /test/Transforms/GVN/pr17732.ll | |
| parent | 5ebdcd29b641ef3e6d32c2921c8cef8906ebdfcd (diff) | |
| download | external_llvm-0ab20588523b59a65a4a29d47184a41443fa9337.zip external_llvm-0ab20588523b59a65a4a29d47184a41443fa9337.tar.gz external_llvm-0ab20588523b59a65a4a29d47184a41443fa9337.tar.bz2 | |
IR: Do not canonicalize constant GEPs into an out-of-bounds array access
Summary:
Consider a GEP of:
i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c, i32 0, i32 0, i64 0)
If we proceeded to GEP the aforementioned object by 8, would form a GEP of:
i8* getelementptr ({ [2 x i8], i32, i8, [3 x i8] }* @main.c, i32 0, i32 0, i64 8)
Note that we would go through the first array member, causing an
out-of-bounds accesses. This is problematic because we might get fooled
if we are trying to evaluate loads using this GEP, for example, based
off of an object with a constant initializer where the array is zero.
This fixes PR17732.
Reviewers: nicholas, chandlerc, void
Reviewed By: void
CC: llvm-commits, echristo, void, aemerson
Differential Revision: http://llvm-reviews.chandlerc.com/D2093
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194220 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'test/Transforms/GVN/pr17732.ll')
| -rw-r--r-- | test/Transforms/GVN/pr17732.ll | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/test/Transforms/GVN/pr17732.ll b/test/Transforms/GVN/pr17732.ll new file mode 100644 index 0000000..606a195 --- /dev/null +++ b/test/Transforms/GVN/pr17732.ll @@ -0,0 +1,30 @@ +; RUN: opt -gvn -S -o - < %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-n8:16:32:64-S128" +target triple = "x86_64-unknown-linux-gnu" + +%struct.with_array = type { [2 x i8], i32, i8 } +%struct.with_vector = type { <2 x i8>, i32, i8 } + +@main.obj_with_array = private unnamed_addr constant { [2 x i8], i32, i8, [3 x i8] } { [2 x i8] zeroinitializer, i32 0, i8 1, [3 x i8] undef }, align 4 +@array_with_zeroinit = common global %struct.with_array zeroinitializer, align 4 + +@main.obj_with_vector = private unnamed_addr constant { <2 x i8>, i32, i8, [3 x i8] } { <2 x i8> zeroinitializer, i32 0, i8 1, [3 x i8] undef }, align 4 +@vector_with_zeroinit = common global %struct.with_vector zeroinitializer, align 4 + +define i32 @main() { +entry: + tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* getelementptr inbounds (%struct.with_array* @array_with_zeroinit, i64 0, i32 0, i64 0), i8* getelementptr inbounds ({ [2 x i8], i32, i8, [3 x i8] }* @main.obj_with_array, i64 0, i32 0, i64 0), i64 12, i32 4, i1 false) + %0 = load i8* getelementptr inbounds (%struct.with_array* @array_with_zeroinit, i64 0, i32 2), align 4 + + tail call void @llvm.memcpy.p0i8.p0i8.i64(i8* getelementptr inbounds (%struct.with_vector* @vector_with_zeroinit, i64 0, i32 0, i64 0), i8* getelementptr inbounds ({ <2 x i8>, i32, i8, [3 x i8] }* @main.obj_with_vector, i64 0, i32 0, i64 0), i64 12, i32 4, i1 false) + %1 = load i8* getelementptr inbounds (%struct.with_vector* @vector_with_zeroinit, i64 0, i32 2), align 4 + %conv0 = sext i8 %0 to i32 + %conv1 = sext i8 %1 to i32 + %and = and i32 %conv0, %conv1 + ret i32 %and +; CHECK-LABEL: define i32 @main( +; CHECK: ret i32 1 +} + +declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture readonly, i64, i32, i1) |