r326872 - Reland r326766 (with a slightly modified test)

[George Burgess IV via cfe-commits]

Author: gbiv
Date: Tue Mar  6 20:52:34 2018
New Revision: 326872

URL: http://llvm.org/viewvc/llvm-project?rev=326872&view=rev
Log:
Reland r326766 (with a slightly modified test)

The original revert was done in r326869, since reverting r326602 broke
the test added by this.

The new test should be less dependent on r326602.

Modified:
    cfe/trunk/lib/AST/ExprConstant.cpp
    cfe/trunk/test/CodeGenCXX/alloc-size.cpp

Modified: cfe/trunk/lib/AST/ExprConstant.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ExprConstant.cpp?rev=326872&r1=326871&r2=326872&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ExprConstant.cpp (original)
+++ cfe/trunk/lib/AST/ExprConstant.cpp Tue Mar  6 20:52:34 2018
@@ -133,7 +133,11 @@ namespace {
 
     E = E->IgnoreParens();
     // If we're doing a variable assignment from e.g. malloc(N), there will
-    // probably be a cast of some kind. Ignore it.
+    // probably be a cast of some kind. In exotic cases, we might also see a
+    // top-level ExprWithCleanups. Ignore them either way.
+    if (const auto *EC = dyn_cast<ExprWithCleanups>(E))
+      E = EC->getSubExpr()->IgnoreParens();
+
     if (const auto *Cast = dyn_cast<CastExpr>(E))
       E = Cast->getSubExpr()->IgnoreParens();
 

Modified: cfe/trunk/test/CodeGenCXX/alloc-size.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/alloc-size.cpp?rev=326872&r1=326871&r2=326872&view=diff
==============================================================================
--- cfe/trunk/test/CodeGenCXX/alloc-size.cpp (original)
+++ cfe/trunk/test/CodeGenCXX/alloc-size.cpp Tue Mar  6 20:52:34 2018
@@ -70,3 +70,19 @@ int testIt() {
          __builtin_object_size(dependent_calloc2<int, 9>(), 0);
 }
 } // namespace templated_alloc_size
+
+// Be sure that an ExprWithCleanups doesn't deter us.
+namespace alloc_size_with_cleanups {
+struct Foo {
+  ~Foo();
+};
+
+void *my_malloc(const Foo &, int N) __attribute__((alloc_size(2)));
+
+// CHECK-LABEL: define i32 lalala
+int testIt() {
+  int *const p = (int *)my_malloc(Foo{}, 3);
+  // CHECK: ret i32 3
+  return __builtin_object_size(p, 0);
+}
+} // namespace alloc_size_with_cleanups