When "low alignment" is specified, then set the alignment of the aggregate's

store to 1. This allows code-gen to select a more appropriate alignment. If left
to zero, an alignment greater than the alignment of the pointer may be selected,
causing code-gen to use instructions which require an alignment greater than the
pointer guarantees.
<rdar://problem/11043589>

llvm-svn: 152951

1 files changed, 36 insertions, 0 deletions

diff --git a/clang/test/CodeGenCXX/2012-03-16-StoreAlign.cpp b/clang/test/CodeGenCXX/2012-03-16-StoreAlign.cpp
new file mode 100644
index 00000000000..c2c7548c221
--- /dev/null
+++ b/clang/test/CodeGenCXX/2012-03-16-StoreAlign.cpp
@@ -0,0 +1,36 @@
+// RUN: %clang_cc1 -emit-llvm -o - -triple x86_64-apple-darwin %s | FileCheck %s
+// <rdar://problem/11043589>
+
+struct Length {
+  Length(double v) {
+    m_floatValue = static_cast<float>(v);
+  }
+
+  bool operator==(const Length& o) const {
+    return getFloatValue() == o.getFloatValue();
+  }
+  bool operator!=(const Length& o) const { return !(*this == o); }
+private:
+  float getFloatValue() const {
+    return m_floatValue;
+  }
+  float m_floatValue;
+};
+
+
+struct Foo {
+  static Length inchLength(double inch);
+  static bool getPageSizeFromName(const Length &A) {
+    static const Length legalWidth = inchLength(8.5);
+    if (A != legalWidth) return true;
+    return false;
+  }
+};
+
+// CHECK: @_ZZN3Foo19getPageSizeFromNameERK6LengthE10legalWidth = linkonce_odr global %struct.Length zeroinitializer, align 4
+// CHECK: store float %call, float* getelementptr inbounds (%struct.Length* @_ZZN3Foo19getPageSizeFromNameERK6LengthE10legalWidth, i32 0, i32 0), align 1
+
+bool bar(Length &b) {
+  Foo f;
+  return f.getPageSizeFromName(b);
+}