Update documentation of HasSideEffects to match its callers' expectations, and

update implementation to match. An elidable, non-trivial constructor call is a
side-effect under this definition, but wasn't under the old one, because we are
not required to evaluate it even though it may have an effect.

Also rationalize checking for volatile reads: just look for lvalue-to-rvalue
conversions on volatile glvalues, and ignore whether a DeclRefExpr etc is for
a volatile variable.

llvm-svn: 161393

1 files changed, 15 insertions, 3 deletions

diff --git a/clang/test/CodeGenCXX/global-init.cpp b/clang/test/CodeGenCXX/global-init.cpp
index da5467ac3f4..2a53ad9e3e7 100644
--- a/clang/test/CodeGenCXX/global-init.cpp
+++ b/clang/test/CodeGenCXX/global-init.cpp
@@ -129,6 +129,14 @@ namespace test6 {
   const std::type_info *const t = &typeid(p);
   // CHECK-NOT: @_ZN5test6L1tE
 
+  extern B *volatile v;
+  // CHECK: store {{.*}} @_ZN5test6L1wE
+  B *const w = dynamic_cast<B*>(v);
+
+  // CHECK: load volatile
+  // CHECK: store {{.*}} @_ZN5test6L1xE
+  const int x = *(volatile int*)0x1234;
+
   namespace {
     int a = int();
     volatile int b = int();
@@ -145,7 +153,7 @@ namespace test6 {
 namespace test7 {
   struct A { A(); };
   struct B { ~B(); int n; };
-  struct C { C() = default; C(const C&); };
+  struct C { C() = default; C(const C&); int n; };
   struct D {};
 
   // CHECK: call void @_ZN5test71AC1Ev({{.*}}@_ZN5test7L1aE)
@@ -161,8 +169,12 @@ namespace test7 {
 
   // CHECK-NOT: @_ZN5test7L2c1E
   // CHECK: @_ZN5test7L2c2E
-  const C c1 = C(); // elidable copy
-  const C c2 = static_cast<C&&>(C()); // non-elidable copy
+  // CHECK-NOT: @_ZN5test7L2c3E
+  // CHECK: @_ZN5test7L2c4E
+  const C c1 = C();
+  const C c2 = static_cast<const C&>(C());
+  const int c3 = C().n;
+  const int c4 = C(C()).n;
 
   // CHECK-NOT: @_ZN5test7L1dE
   const D d = D();