Add element-atomic mem intrinsic canary tests for Address Sanitizer.

[dneilson]

Summary

Add canary tests to verify that ASAN currently does nothing with the element atomic memory intrinsics for memcpy, memmove, and memset.

Placeholder tests that will fail once element atomic @llvm.mem[cpy|move|set] instrinsics have been added to the MemIntrinsic class hierarchy. These will act as a reminder to verify that ASAN handles these intrinsics properly once they have been added to that class hierarchy.

[reames]

LGTM

llvm/trunk/test/Instrumentation/AddressSanitizer/basic.ll

 }
 
 ; CHECK-LABEL: memintr_test
 ; CHECK: __asan_memset
 ; CHECK: __asan_memmove
 ; CHECK: __asan_memcpy
 ; CHECK: ret void
 
+declare void @llvm.memset.element.unordered.atomic.p0i8.i64(i8* nocapture writeonly, i8, i64, i32) nounwind
+declare void @llvm.memmove.element.unordered.atomic.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32) nounwind
+declare void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32) nounwind
+
+define void @memintr_element_atomic_test(i8* %a, i8* %b) nounwind uwtable sanitize_address {
+  ; This is a canary test to make sure that these don't get lowered into calls that don't
+  ; have the element-atomic property. Eventually, asan will have to be enhanced to lower
+  ; these properly.
+  ; CHECK-LABEL: memintr_element_atomic_test
+  ; CHECK-NEXT: tail call void @llvm.memset.element.unordered.atomic.p0i8.i64(i8* align 1 %a, i8 0, i64 100, i32 1)
+  ; CHECK-NEXT: tail call void @llvm.memmove.element.unordered.atomic.p0i8.p0i8.i64(i8* align 1 %a, i8* align 1 %b, i64 100, i32 1)
+  ; CHECK-NEXT: tail call void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i64(i8* align 1 %a, i8* align 1 %b, i64 100, i32 1)
+  ; CHECK-NEXT: ret void
+  tail call void @llvm.memset.element.unordered.atomic.p0i8.i64(i8* align 1 %a, i8 0, i64 100, i32 1)
+  tail call void @llvm.memmove.element.unordered.atomic.p0i8.p0i8.i64(i8* align 1 %a, i8* align 1 %b, i64 100, i32 1)
+  tail call void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i64(i8* align 1 %a, i8* align 1 %b, i64 100, i32 1)
+  ret void
+}
+
+
 ; CHECK-LABEL: @test_swifterror
 ; CHECK-NOT: __asan_report_load
 ; CHECK: ret void
 define void @test_swifterror(i8** swifterror) sanitize_address {
   %swifterror_ptr_value = load i8*, i8** %0
   ret void
 }