c++: array new with value-initialization [PR115645]
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Commit Message
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/branches?
-- >8 --
This extends the r11-5179 fix which doesn't work with multidimensional
arrays. In particular,
struct S {
explicit S() { }
};
auto p = new S[1][1]();
should not say "converting to S from initializer list would use
explicit constructor" because there's no {}. However, since we
went into the block where we create a {}, we got confused. We
should not have gotten there but we did because array_p was true.
This patch refines the check once more.
PR c++/115645
gcc/cp/ChangeLog:
* init.cc (build_new): Don't do any deduction for arrays with
bounds if it's value-initialized.
gcc/testsuite/ChangeLog:
* g++.dg/expr/anew7.C: New test.
---
gcc/cp/init.cc | 12 ++++++++----
gcc/testsuite/g++.dg/expr/anew7.C | 13 +++++++++++++
2 files changed, 21 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/expr/anew7.C
base-commit: 1250540a98e0a1dfa4d7834672d88d8543ea70b1
Comments
On 7/2/24 4:43 PM, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/branches?
OK.
> -- >8 --
> This extends the r11-5179 fix which doesn't work with multidimensional
> arrays. In particular,
>
> struct S {
> explicit S() { }
> };
> auto p = new S[1][1]();
>
> should not say "converting to S from initializer list would use
> explicit constructor" because there's no {}. However, since we
> went into the block where we create a {}, we got confused. We
> should not have gotten there but we did because array_p was true.
>
> This patch refines the check once more.
>
> PR c++/115645
>
> gcc/cp/ChangeLog:
>
> * init.cc (build_new): Don't do any deduction for arrays with
> bounds if it's value-initialized.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/expr/anew7.C: New test.
> ---
> gcc/cp/init.cc | 12 ++++++++----
> gcc/testsuite/g++.dg/expr/anew7.C | 13 +++++++++++++
> 2 files changed, 21 insertions(+), 4 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/expr/anew7.C
>
> diff --git a/gcc/cp/init.cc b/gcc/cp/init.cc
> index 826a31c4a84..e9561c146d7 100644
> --- a/gcc/cp/init.cc
> +++ b/gcc/cp/init.cc
> @@ -4005,10 +4005,14 @@ build_new (location_t loc, vec<tree, va_gc> **placement, tree type,
> /* P1009: Array size deduction in new-expressions. */
> const bool array_p = TREE_CODE (type) == ARRAY_TYPE;
> if (*init
> - /* If ARRAY_P, we have to deduce the array bound. For C++20 paren-init,
> - we have to process the parenthesized-list. But don't do it for (),
> - which is value-initialization, and INIT should stay empty. */
> - && (array_p || (cxx_dialect >= cxx20 && nelts && !(*init)->is_empty ())))
> + /* If the array didn't specify its bound, we have to deduce it. */
> + && ((array_p && !TYPE_DOMAIN (type))
> + /* For C++20 array with parenthesized-init, we have to process
> + the parenthesized-list. But don't do it for (), which is
> + value-initialization, and INIT should stay empty. */
> + || (cxx_dialect >= cxx20
> + && (array_p || nelts)
> + && !(*init)->is_empty ())))
> {
> /* This means we have 'new T[]()'. */
> if ((*init)->is_empty ())
> diff --git a/gcc/testsuite/g++.dg/expr/anew7.C b/gcc/testsuite/g++.dg/expr/anew7.C
> new file mode 100644
> index 00000000000..ead5536e109
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/expr/anew7.C
> @@ -0,0 +1,13 @@
> +// PR c++/115645
> +// { dg-do compile { target c++11 } }
> +
> +struct S {
> + explicit S() { }
> +};
> +
> +auto p = new S[1][1]();
> +auto q = new S[1][1]{}; // { dg-error "explicit" }
> +auto r = new S[1]();
> +auto s = new S[1]{}; // { dg-error "explicit" }
> +auto t = new S[1][1][1]();
> +auto u = new S[1][1][1]{}; // { dg-error "explicit" }
>
> base-commit: 1250540a98e0a1dfa4d7834672d88d8543ea70b1
@@ -4005,10 +4005,14 @@ build_new (location_t loc, vec<tree, va_gc> **placement, tree type,
/* P1009: Array size deduction in new-expressions. */
const bool array_p = TREE_CODE (type) == ARRAY_TYPE;
if (*init
- /* If ARRAY_P, we have to deduce the array bound. For C++20 paren-init,
- we have to process the parenthesized-list. But don't do it for (),
- which is value-initialization, and INIT should stay empty. */
- && (array_p || (cxx_dialect >= cxx20 && nelts && !(*init)->is_empty ())))
+ /* If the array didn't specify its bound, we have to deduce it. */
+ && ((array_p && !TYPE_DOMAIN (type))
+ /* For C++20 array with parenthesized-init, we have to process
+ the parenthesized-list. But don't do it for (), which is
+ value-initialization, and INIT should stay empty. */
+ || (cxx_dialect >= cxx20
+ && (array_p || nelts)
+ && !(*init)->is_empty ())))
{
/* This means we have 'new T[]()'. */
if ((*init)->is_empty ())
new file mode 100644
@@ -0,0 +1,13 @@
+// PR c++/115645
+// { dg-do compile { target c++11 } }
+
+struct S {
+ explicit S() { }
+};
+
+auto p = new S[1][1]();
+auto q = new S[1][1]{}; // { dg-error "explicit" }
+auto r = new S[1]();
+auto s = new S[1]{}; // { dg-error "explicit" }
+auto t = new S[1][1][1]();
+auto u = new S[1][1][1]{}; // { dg-error "explicit" }