gimplify_init_constructor() only attempts to gimplify a CONSTRUCTOR's
elts under two conditions: if the object has not been zero-initialized,
or if categorize_ctor_elements() detected more than one "nonzero" elt in
the CONSTRUCTOR. With the PR's testcase, both of these conditions are
false: the gimplifier decides to zero-initialize the object (apparently
because one of the object's field was not initialized), and
categorize_ctor_elements() rightly does not count an empty struct field
as a non-zero component of the CONSTRUCTOR (so num_nonzero_elements
remains 0). So we end up not emitting the call to field "A a"'s
constructor.
In order to fix this issue, I think we should unconditionally call
gimplify_init_ctor_eval even if we have cleared the object and even if
the object has no nonzero elements. Because even so, one of the
constructor's elts may be side-effecting and in such a case we would
still want to emit it. The function already has logic to skip over
redundant zero-initializations so we should be safe in that regard.
Bootstrap and regtesting (including fortran + ada) on x86_64-unknown-linux-gnu
in progress. OK for trunk if it succeeds?
gcc/
PR c++/64527
* gcc/gimplify.c (gimplify_init_constructor): Unconditionally
call gimplify_init_ctor_eval.
gcc/testsuite/
* g++.dg/init/pr64527.C: New test.
---
gcc/gimplify.c | 6 +-----
gcc/testsuite/g++.dg/init/pr64527.C | 21 +++++++++++++++++++++
2 files changed, 22 insertions(+), 5 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/init/pr64527.C
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index ff0a225..5158243 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -4005,11 +4005,7 @@ gimplify_init_constructor (tree *expr_p, gimple_seq
*pre_p, gimple_seq *post_p,
gimplify_stmt (expr_p, pre_p);
}
- /* If we have not block cleared the object, or if there are nonzero
- elements in the constructor, add assignments to the individual
- scalar fields of the object. */
- if (!cleared || num_nonzero_elements > 0)
- gimplify_init_ctor_eval (object, elts, pre_p, cleared);
+ gimplify_init_ctor_eval (object, elts, pre_p, cleared);
*expr_p = NULL_TREE;
}
diff --git a/gcc/testsuite/g++.dg/init/pr64527.C
b/gcc/testsuite/g++.dg/init/pr64527.C
new file mode 100644
index 0000000..36b8214
--- /dev/null
+++ b/gcc/testsuite/g++.dg/init/pr64527.C
@@ -0,0 +1,21 @@
+// { dg-do run { target c++11 } }
+
+static int g;
+
+struct A {
+ A() { g = 1; }
+};
+
+struct accessor {
+ A a;
+ int x;
+};
+
+int
+main (void)
+{
+ (void) accessor{};
+
+ if (g != 1)
+ __builtin_abort ();
+}
--
2.4.0.rc2
