On 2/5/23 09:57, Patrick Palka wrote:
On Sat, 4 Feb 2023, Jason Merrill wrote:
On 2/4/23 20:41, Jason Merrill wrote:
On 2/4/23 20:08, Patrick Palka wrote:
On Sat, 4 Feb 2023, Jason Merrill wrote:
On 2/4/23 15:31, Patrick Palka wrote:
After r13-5684-g59e0376f607805 the (pruned) callee of a non-dependent
CALL_EXPR is a bare FUNCTION_DECL rather than ADDR_EXPR of
FUNCTION_DECL.
This innocent change revealed that cp_tree_equal doesn't first check
dependentness of a CALL_EXPR before treating the callee as a dependent
name, which manifests as us incorrectly accepting the first two
testcases below and rejecting the third:
* In the first testcase, cp_tree_equal incorrectly returns true for
the two non-dependent CALL_EXPRs f(0) and f(0) (whose
CALL_EXPR_FN
are different FUNCTION_DECLs) and so we treat #2 as a
redeclaration
of #1.
* Same issue in the second testcase, for f<int*>() and f<char>().
* In the third testcase, cp_tree_equal incorrectly returns true for
f<int>() and f<void(*)(int)>() which causes us to conflate the
two
dependent specializations A<decltype(f<int>()(U()))> and
A<decltype(f<void(*)(int)>()(U()))>, leading to a bogus error.
This patch fixes this by making called_fns_equal treat two callees as
dependent names only if the CALL_EXPRs in question are dependent.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK
for
trunk/12? Patch generated with -w to ignore noisy whitespace changes.
PR c++/107461
gcc/cp/ChangeLog:
* pt.cc (iterative_hash_template_arg) <case CALL_EXPR>: Treat
the callee as a dependent name only if the CALL_EXPR is
dependent.
* tree.cc (called_fns_equal): Take two CALL_EXPRs instead of
CALL_EXPR_FNs thereof. As above.
(cp_tree_equal) <case CALL_EXPR>: Adjust call to called_fns_equal.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/overload5.C: New test.
* g++.dg/cpp0x/overload5a.C: New test.
* g++.dg/cpp0x/overload6.C: New test.
---
gcc/cp/pt.cc | 1 +
gcc/cp/tree.cc | 33
++++++++++++++-----------
gcc/testsuite/g++.dg/cpp0x/overload5.C | 12 +++++++++
gcc/testsuite/g++.dg/cpp0x/overload5a.C | 10 ++++++++
gcc/testsuite/g++.dg/cpp0x/overload6.C | 16 ++++++++++++
5 files changed, 58 insertions(+), 14 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload5.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload5a.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload6.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 255332dc0c1..c9360240cd2 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -1841,6 +1841,7 @@ iterative_hash_template_arg (tree arg, hashval_t
val)
case CALL_EXPR:
{
tree fn = CALL_EXPR_FN (arg);
+ if (TREE_TYPE (arg) == NULL_TREE)
How about changing dependent_name to take the CALL_EXPR rather than the
CALL_EXPR_FN? That would mean some changes to write_expression to move
the
dependent_name handling into the CALL_EXPR handling, but that doesn't
seem
like a bad thing. Other callers seem like a trivial change.
Indeed changing dependent_name seems best, but I'm worried about such a
refactoring to write_expression causing unintended mangling changes at
this stage. Because it seems the CALL_EXPR case of write_expression
isn't the user of the dependent_name branch of write_expression, at
least according to the following patch which causes us to ICE on
mangle{37,57,58,76}.C:
Yeah, I tried the same thing. Maybe for GCC 13 better to add a new function
rather than change the current one.
Sounds good, like so? Only regtested so far. Full bootstrap and
regtest running on x86_64-pc-linux-gnu.
-- >8 --
Subject: [PATCH] c++: equivalence of non-dependent calls [PR107461]
After r13-5684-g59e0376f607805 the (pruned) callee of a non-dependent
CALL_EXPR is a bare FUNCTION_DECL rather than ADDR_EXPR of FUNCTION_DECL.
This innocent change revealed that cp_tree_equal doesn't first check
dependentness of a CALL_EXPR before treating a FUNCTION_DECL callee as a
dependent name, which manifests as us incorrectly accepting the first
two testcases below and rejecting the third:
* In the first testcase, cp_tree_equal incorrectly returns true for
the two non-dependent CALL_EXPRs f(0) and f(0) (whose CALL_EXPR_FN
are different FUNCTION_DECLs) and so we treat #2 as a redeclaration
of #1.
* Same issue in the second testcase, for f<int*>() and f<char>().
* In the third testcase, cp_tree_equal incorrectly returns true for
f<int>() and f<void(*)(int)>() which causes us to conflate the two
dependent specializations A<decltype(f<int>()(U()))> and
A<decltype(f<void(*)(int)>()(U()))>, leading to a bogus error.
This patch fixes this by making called_fns_equal treat two callees as
dependent names only if the overall CALL_EXPRs are dependent, via a new
convenience function call_expr_dependent_name that is like dependent_name
but also checks dependence of the overall CALL_EXPR.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk/12? Patch generated with -w to ignore noisy whitespace changes.
OK, thanks.
PR c++/107461
gcc/cp/ChangeLog:
* cp-tree.h (call_expr_dependent_name): Declare.
* pt.cc (iterative_hash_template_arg) <case CALL_EXPR>: Use
call_expr_dependent_name instead of dependent_name.
* tree.cc (call_expr_dependent_name): Define.
(called_fns_equal): Adjust to take two CALL_EXPRs instead of
CALL_EXPR_FNs thereof. Use call_expr_dependent_name instead
of dependent_name.
(cp_tree_equal) <case CALL_EXPR>: Adjust call to called_fns_equal.
gcc/testsuite/ChangeLog:
* g++.dg/cpp0x/overload5.C: New test.
* g++.dg/cpp0x/overload5a.C: New test.
* g++.dg/cpp0x/overload6.C: New test.
---
gcc/cp/cp-tree.h | 1 +
gcc/cp/pt.cc | 2 +-
gcc/cp/tree.cc | 24 +++++++++++++++++++-----
gcc/testsuite/g++.dg/cpp0x/overload5.C | 12 ++++++++++++
gcc/testsuite/g++.dg/cpp0x/overload5a.C | 10 ++++++++++
gcc/testsuite/g++.dg/cpp0x/overload6.C | 16 ++++++++++++++++
6 files changed, 59 insertions(+), 6 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload5.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload5a.C
create mode 100644 gcc/testsuite/g++.dg/cpp0x/overload6.C
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 00b2bffc85c..ef601182d4b 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -7902,6 +7902,7 @@ extern tree lookup_maybe_add (tree
fns, tree lookup,
extern int is_overloaded_fn (tree) ATTRIBUTE_PURE;
extern bool really_overloaded_fn (tree) ATTRIBUTE_PURE;
extern tree dependent_name (tree);
+extern tree call_expr_dependent_name (tree);
extern tree maybe_get_fns (tree) ATTRIBUTE_PURE;
extern tree get_fns (tree) ATTRIBUTE_PURE;
extern tree get_first_fn (tree) ATTRIBUTE_PURE;
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 255332dc0c1..9f3fc1fa089 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -1841,7 +1841,7 @@ iterative_hash_template_arg (tree arg, hashval_t val)
case CALL_EXPR:
{
tree fn = CALL_EXPR_FN (arg);
- if (tree name = dependent_name (fn))
+ if (tree name = call_expr_dependent_name (arg))
{
if (TREE_CODE (fn) == TEMPLATE_ID_EXPR)
val = iterative_hash_template_arg (TREE_OPERAND (fn, 1), val);
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index c1da868732b..880bd4f9bcf 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -2608,6 +2608,18 @@ dependent_name (tree x)
return NULL_TREE;
}
+/* Like dependent_name, but takes the overall CALL_EXPR and checks its
+ dependence. */
+
+tree
+call_expr_dependent_name (tree x)
+{
+ if (TREE_TYPE (x) != NULL_TREE)
+ /* X isn't dependent, so its callee isn't a dependent name. */
+ return NULL_TREE;
+ return dependent_name (CALL_EXPR_FN (x));
+}
+
/* Returns true iff X is an expression for an overloaded function
whose type cannot be known without performing overload
resolution. */
@@ -3870,16 +3882,18 @@ decl_internal_context_p (const_tree decl)
return !TREE_PUBLIC (decl);
}
-/* Subroutine of cp_tree_equal: t1 and t2 are the CALL_EXPR_FNs of two
- CALL_EXPRS. Return whether they are equivalent. */
+/* Subroutine of cp_tree_equal: t1 and t2 are two CALL_EXPRs.
+ Return whether their CALL_EXPR_FNs are equivalent. */
static bool
called_fns_equal (tree t1, tree t2)
{
/* Core 1321: dependent names are equivalent even if the overload sets
are different. But do compare explicit template arguments. */
- tree name1 = dependent_name (t1);
- tree name2 = dependent_name (t2);
+ tree name1 = call_expr_dependent_name (t1);
+ tree name2 = call_expr_dependent_name (t2);
+ t1 = CALL_EXPR_FN (t1);
+ t2 = CALL_EXPR_FN (t2);
if (name1 || name2)
{
tree targs1 = NULL_TREE, targs2 = NULL_TREE;
@@ -4037,7 +4051,7 @@ cp_tree_equal (tree t1, tree t2)
if (KOENIG_LOOKUP_P (t1) != KOENIG_LOOKUP_P (t2))
return false;
- if (!called_fns_equal (CALL_EXPR_FN (t1), CALL_EXPR_FN (t2)))
+ if (!called_fns_equal (t1, t2))
return false;
call_expr_arg_iterator iter1, iter2;
diff --git a/gcc/testsuite/g++.dg/cpp0x/overload5.C
b/gcc/testsuite/g++.dg/cpp0x/overload5.C
new file mode 100644
index 00000000000..e05b1594f51
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/overload5.C
@@ -0,0 +1,12 @@
+// PR c++/107461
+// { dg-do compile { target c++11 } }
+
+int f(...);
+template<class T> decltype(T() + f(0)) g(); // #1
+
+char f(int);
+template<class T> decltype(T() + f(0)) g(); // #2, distinct from #1
+
+int main() {
+ g<int>(); // { dg-error "ambiguous" }
+}
diff --git a/gcc/testsuite/g++.dg/cpp0x/overload5a.C
b/gcc/testsuite/g++.dg/cpp0x/overload5a.C
new file mode 100644
index 00000000000..037114f199c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/overload5a.C
@@ -0,0 +1,10 @@
+// PR c++/107461
+// { dg-do compile { target c++11 } }
+
+template<class T> T f();
+template<class T> decltype(T() + f<int*>()) g(); // #1
+template<class T> decltype(T() + f<char>()) g(); // #2, distinct from #1
+
+int main() {
+ g<int>(); // { dg-error "ambiguous" }
+}
diff --git a/gcc/testsuite/g++.dg/cpp0x/overload6.C
b/gcc/testsuite/g++.dg/cpp0x/overload6.C
new file mode 100644
index 00000000000..1fbee0501de
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/overload6.C
@@ -0,0 +1,16 @@
+// PR c++/107461
+// { dg-do compile { target c++11 } }
+
+template<class T> T f();
+
+template<class> struct A { };
+
+template<class T> struct B {
+ template<class U, class = A<decltype(f<T>()(U()))>>
+ static void g(U);
+};
+
+int main() {
+ B<int> b;
+ B<void(*)(int)>::g(0); // { dg-bogus "no match" }
+}
