* [PATCH] c++: bound ttp level lowering [PR109531]
@ 2023-04-17 18:44 Patrick Palka
2023-04-17 22:11 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Patrick Palka @ 2023-04-17 18:44 UTC (permalink / raw)
To: gcc-patches; +Cc: jason, Patrick Palka
Here when level lowering the bound ttp TT<typename T::type> via the
substitution T=C, we're neglecting to canonicalize (and therefore strip
of simple typedefs) the resulting template arguments {A<int>} before
determining its new canonical type via hash table lookup. This leads to
an a hash mismatch ICE for the two equivalent types TT<int> and TT<A<int>>
since iterative_hash_template_arg misbehaves for a non-canonicalized type
argument.
We can fix this by canonicalizing or coercing the substituted arguments
directly, but given that creation and ordinary substitution of bound
ttps both go through lookup_template_class, which in turn performs
coercion/canonicalization, it seems best to make this code path go
through lookup_template_class as well.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk/13?
PR c++/109531
gcc/cp/ChangeLog:
* pt.cc (tsubst) <case BOUND_TEMPLATE_TEMPLATE_PARM>:
In the level-lowering case just use lookup_template_class
to rebuild the bound ttp.
gcc/testsuite/ChangeLog:
* g++.dg/template/canon-type-20.C: New test.
* g++.dg/template/ttp36.C: New test.
---
gcc/cp/pt.cc | 39 ++++++++++---------
gcc/testsuite/g++.dg/template/canon-type-20.C | 18 +++++++++
gcc/testsuite/g++.dg/template/ttp36.C | 12 ++++++
3 files changed, 50 insertions(+), 19 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/template/canon-type-20.C
create mode 100644 gcc/testsuite/g++.dg/template/ttp36.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index fcc8e0d1d57..e065ace5c55 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -16232,7 +16232,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
{
case TEMPLATE_TYPE_PARM:
case TEMPLATE_TEMPLATE_PARM:
- case BOUND_TEMPLATE_TEMPLATE_PARM:
if (cp_type_quals (t))
{
r = tsubst (TYPE_MAIN_VARIANT (t), args, complain, in_decl);
@@ -16274,24 +16273,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
only instantiated during satisfaction. */
PLACEHOLDER_TYPE_CONSTRAINTS_INFO (r) = ci;
- if (code == BOUND_TEMPLATE_TEMPLATE_PARM)
- {
- tree tinfo = TYPE_TEMPLATE_INFO (t);
- /* We might need to substitute into the types of non-type
- template parameters. */
- tree tmpl = tsubst (TI_TEMPLATE (tinfo), args,
- complain, in_decl);
- if (tmpl == error_mark_node)
- return error_mark_node;
- tree argvec = tsubst (TI_ARGS (tinfo), args,
- complain, in_decl);
- if (argvec == error_mark_node)
- return error_mark_node;
-
- TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (r)
- = build_template_info (tmpl, argvec);
- }
-
if (TYPE_STRUCTURAL_EQUALITY_P (t))
SET_TYPE_STRUCTURAL_EQUALITY (r);
else
@@ -16299,6 +16280,26 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
}
break;
+ case BOUND_TEMPLATE_TEMPLATE_PARM:
+ {
+ tree tinfo = TYPE_TEMPLATE_INFO (t);
+ /* We might need to substitute into the types of non-type
+ template parameters. This also lowers the level of
+ the ttp appropriately. */
+ tree tmpl = tsubst (TI_TEMPLATE (tinfo), args,
+ complain, in_decl);
+ if (tmpl == error_mark_node)
+ return error_mark_node;
+ tree argvec = tsubst (TI_ARGS (tinfo), args,
+ complain, in_decl);
+ if (argvec == error_mark_node)
+ return error_mark_node;
+ r = lookup_template_class (tmpl, argvec, in_decl, NULL_TREE,
+ /*entering_scope=*/false, complain);
+ r = cp_build_qualified_type (r, cp_type_quals (t), complain);
+ break;
+ }
+
case TEMPLATE_PARM_INDEX:
/* OK, now substitute the type of the non-type parameter. We
couldn't do it earlier because it might be an auto parameter,
diff --git a/gcc/testsuite/g++.dg/template/canon-type-20.C b/gcc/testsuite/g++.dg/template/canon-type-20.C
new file mode 100644
index 00000000000..e40261037e5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/canon-type-20.C
@@ -0,0 +1,18 @@
+// PR c++/109531
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "--param=hash-table-verification-limit=1000" }
+
+template<class T>
+using A = int;
+
+struct B { using type = int; };
+struct C { using type = A<int>; };
+
+template<class T>
+struct D {
+ template<template<class> class TT>
+ TT<typename T::type> f ();
+};
+
+template struct D<B>;
+template struct D<C>;
diff --git a/gcc/testsuite/g++.dg/template/ttp36.C b/gcc/testsuite/g++.dg/template/ttp36.C
new file mode 100644
index 00000000000..2df00855cf7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/ttp36.C
@@ -0,0 +1,12 @@
+// Verify we propagate cv-quals when level-lowering a bound ttp.
+
+template<class T>
+struct B {
+ template<template<class> class TT>
+ void f(const TT<T> *);
+
+ template<template<class> class TT>
+ void f(TT<T> *); // { dg-bogus "cannot be overloaded" }
+};
+
+template struct B<int>;
--
2.40.0.335.g9857273be0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] c++: bound ttp level lowering [PR109531]
2023-04-17 18:44 [PATCH] c++: bound ttp level lowering [PR109531] Patrick Palka
@ 2023-04-17 22:11 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2023-04-17 22:11 UTC (permalink / raw)
To: Patrick Palka, gcc-patches
On 4/17/23 14:44, Patrick Palka wrote:
> Here when level lowering the bound ttp TT<typename T::type> via the
> substitution T=C, we're neglecting to canonicalize (and therefore strip
> of simple typedefs) the resulting template arguments {A<int>} before
> determining its new canonical type via hash table lookup. This leads to
> an a hash mismatch ICE for the two equivalent types TT<int> and TT<A<int>>
> since iterative_hash_template_arg misbehaves for a non-canonicalized type
> argument.
>
> We can fix this by canonicalizing or coercing the substituted arguments
> directly, but given that creation and ordinary substitution of bound
> ttps both go through lookup_template_class, which in turn performs
> coercion/canonicalization, it seems best to make this code path go
> through lookup_template_class as well.
>
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk/13?
OK.
> PR c++/109531
>
> gcc/cp/ChangeLog:
>
> * pt.cc (tsubst) <case BOUND_TEMPLATE_TEMPLATE_PARM>:
> In the level-lowering case just use lookup_template_class
> to rebuild the bound ttp.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/template/canon-type-20.C: New test.
> * g++.dg/template/ttp36.C: New test.
> ---
> gcc/cp/pt.cc | 39 ++++++++++---------
> gcc/testsuite/g++.dg/template/canon-type-20.C | 18 +++++++++
> gcc/testsuite/g++.dg/template/ttp36.C | 12 ++++++
> 3 files changed, 50 insertions(+), 19 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/template/canon-type-20.C
> create mode 100644 gcc/testsuite/g++.dg/template/ttp36.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index fcc8e0d1d57..e065ace5c55 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -16232,7 +16232,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
> {
> case TEMPLATE_TYPE_PARM:
> case TEMPLATE_TEMPLATE_PARM:
> - case BOUND_TEMPLATE_TEMPLATE_PARM:
> if (cp_type_quals (t))
> {
> r = tsubst (TYPE_MAIN_VARIANT (t), args, complain, in_decl);
> @@ -16274,24 +16273,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
> only instantiated during satisfaction. */
> PLACEHOLDER_TYPE_CONSTRAINTS_INFO (r) = ci;
>
> - if (code == BOUND_TEMPLATE_TEMPLATE_PARM)
> - {
> - tree tinfo = TYPE_TEMPLATE_INFO (t);
> - /* We might need to substitute into the types of non-type
> - template parameters. */
> - tree tmpl = tsubst (TI_TEMPLATE (tinfo), args,
> - complain, in_decl);
> - if (tmpl == error_mark_node)
> - return error_mark_node;
> - tree argvec = tsubst (TI_ARGS (tinfo), args,
> - complain, in_decl);
> - if (argvec == error_mark_node)
> - return error_mark_node;
> -
> - TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (r)
> - = build_template_info (tmpl, argvec);
> - }
> -
> if (TYPE_STRUCTURAL_EQUALITY_P (t))
> SET_TYPE_STRUCTURAL_EQUALITY (r);
> else
> @@ -16299,6 +16280,26 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
> }
> break;
>
> + case BOUND_TEMPLATE_TEMPLATE_PARM:
> + {
> + tree tinfo = TYPE_TEMPLATE_INFO (t);
> + /* We might need to substitute into the types of non-type
> + template parameters. This also lowers the level of
> + the ttp appropriately. */
> + tree tmpl = tsubst (TI_TEMPLATE (tinfo), args,
> + complain, in_decl);
> + if (tmpl == error_mark_node)
> + return error_mark_node;
> + tree argvec = tsubst (TI_ARGS (tinfo), args,
> + complain, in_decl);
> + if (argvec == error_mark_node)
> + return error_mark_node;
> + r = lookup_template_class (tmpl, argvec, in_decl, NULL_TREE,
> + /*entering_scope=*/false, complain);
> + r = cp_build_qualified_type (r, cp_type_quals (t), complain);
> + break;
> + }
> +
> case TEMPLATE_PARM_INDEX:
> /* OK, now substitute the type of the non-type parameter. We
> couldn't do it earlier because it might be an auto parameter,
> diff --git a/gcc/testsuite/g++.dg/template/canon-type-20.C b/gcc/testsuite/g++.dg/template/canon-type-20.C
> new file mode 100644
> index 00000000000..e40261037e5
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/canon-type-20.C
> @@ -0,0 +1,18 @@
> +// PR c++/109531
> +// { dg-do compile { target c++11 } }
> +// { dg-additional-options "--param=hash-table-verification-limit=1000" }
> +
> +template<class T>
> +using A = int;
> +
> +struct B { using type = int; };
> +struct C { using type = A<int>; };
> +
> +template<class T>
> +struct D {
> + template<template<class> class TT>
> + TT<typename T::type> f ();
> +};
> +
> +template struct D<B>;
> +template struct D<C>;
> diff --git a/gcc/testsuite/g++.dg/template/ttp36.C b/gcc/testsuite/g++.dg/template/ttp36.C
> new file mode 100644
> index 00000000000..2df00855cf7
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/template/ttp36.C
> @@ -0,0 +1,12 @@
> +// Verify we propagate cv-quals when level-lowering a bound ttp.
> +
> +template<class T>
> +struct B {
> + template<template<class> class TT>
> + void f(const TT<T> *);
> +
> + template<template<class> class TT>
> + void f(TT<T> *); // { dg-bogus "cannot be overloaded" }
> +};
> +
> +template struct B<int>;
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