On 2/20/20 11:52 AM, Marek Polacek wrote:
On Thu, Feb 20, 2020 at 12:13:07AM +0000, Jason Merrill wrote:
On 2/19/20 10:15 PM, Marek Polacek wrote:
On Fri, Feb 14, 2020 at 12:24:30AM +0100, Jason Merrill wrote:
On 2/11/20 8:54 PM, Marek Polacek wrote:
Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we
attempt to value-initialize in build_vec_init even when there's no
initializer but the type has a constexpr default constructor. But
build_value_init doesn't work in templates, so I think let's avoid
this scenario; we'll go to the normal build_aggr_init path then.
Bootstrapped/regtested on x86_64-linux, ok for trunk and branches?
PR c++/93676 - value-init crash in template.
* init.c (build_vec_init): Don't perform value-init in a template.
Hmm, we really shouldn't even be calling build_vec_init in a template, that
builds up a lot of garbage that we'll throw away at the end of build_new.
Ah, it's true that build_new will just creates a NEW_EXPR in a template and
doesn't use the result of build_new_1. Unfortunately I can't just call
build_special_member_call like we do in build_new_1 since that crashes for
array types.
We should call it for strip_array_types (type).
Since build_special_member_call takes an expression we'd have to modify
its type which I think is not pretty, but it works. Is this along the
lines you had in mind?
I think I still like the v1 patch best but if you're fine with the
following, then am I.
-- >8 --
Since <https://gcc.gnu.org/ml/gcc-patches/2015-02/msg00556.html> we
attempt to value-initialize in build_vec_init even when there's no
initializer but the type has a constexpr default constructor. But
build_value_init doesn't work in templates, and build_vec_init
creates a lot of garbage that would not be used anyway, so don't
call it in a template.
PR c++/93676 - value-init crash in template.
* init.c (build_new_1): Don't call build_vec_init in a template.
* g++.dg/cpp0x/nsdmi-template19.C: New test.
---
gcc/cp/init.c | 6 +++++-
gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C | 13 +++++++++++++
2 files changed, 18 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/nsdmi-template19.C
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index d480660445e..c60f332313a 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -3511,13 +3511,17 @@ build_new_1 (vec<tree, va_gc> **placement, tree type,
tree nelts,
explicit_value_init_p = true;
}
- if (processing_template_decl && explicit_value_init_p)
+ if (processing_template_decl)
{
/* build_value_init doesn't work in templates, and we don't need
the initializer anyway since we're going to throw it away and
rebuild it at instantiation time, so just build up a single
constructor call to get any appropriate diagnostics. */
init_expr = cp_build_fold_indirect_ref (data_addr);
+ /* Avoid an ICE when converting to a base in build_simple_base_path.
+ We'll throw this all away anyway, and build_new will create
+ a NEW_EXPR. */
+ TREE_TYPE (init_expr) = strip_array_types (TREE_TYPE (init_expr));
instead of this, how about casting data_addr to elt_type* before
cp_build_fold_indirect_ref?
Jason
