From 3420ae489c0a8874fc09cdd9d4ea661b8157b07c Mon Sep 17 00:00:00 2001 From: Wei Mi Date: Fri, 8 Sep 2017 17:07:32 +0000 Subject: Use EmitPointerWithAlignment to get alignment information of the pointer used in atomic expr. This is to fix PR34347. EmitAtomicExpr now only uses alignment information from Type, instead of Decl, so when the declaration of an atomic variable is marked to have the alignment equal as its size, EmitAtomicExpr doesn't know about it and will generate libcall instead of atomic op. The patch uses EmitPointerWithAlignment to get the precise alignment information. Differential Revision: https://reviews.llvm.org/D37310 llvm-svn: 312801 --- clang/test/CodeGenCXX/atomic-align.cpp | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) create mode 100644 clang/test/CodeGenCXX/atomic-align.cpp (limited to 'clang/test/CodeGenCXX/atomic-align.cpp') diff --git a/clang/test/CodeGenCXX/atomic-align.cpp b/clang/test/CodeGenCXX/atomic-align.cpp new file mode 100644 index 00000000000..9852ac38a6c --- /dev/null +++ b/clang/test/CodeGenCXX/atomic-align.cpp @@ -0,0 +1,30 @@ +// RUN: %clang_cc1 %s -std=c++11 -emit-llvm -o - -triple=x86_64-linux-gnu | FileCheck %s + +struct AM { + int f1, f2; +}; +alignas(8) AM m; +AM load1() { + AM am; + // m is declared to align to 8bytes, so generate load atomic instead + // of libcall. + // CHECK-LABEL: @_Z5load1v + // CHECK: load atomic {{.*}} monotonic + __atomic_load(&m, &am, 0); + return am; +} + +struct BM { + int f1; + alignas(8) AM f2; +}; +BM bm; +AM load2() { + AM am; + // BM::f2 is declared to align to 8bytes, so generate load atomic instead + // of libcall. + // CHECK-LABEL: @_Z5load2v + // CHECK: load atomic {{.*}} monotonic + __atomic_load(&bm.f2, &am, 0); + return am; +} -- cgit v1.2.3