On Wed, Dec 6, 2017 at 4:40 PM, Jason Merrill <ja...@redhat.com> wrote:
> In this testcase, we consider the initializer of b to decide if it's
> value-dependent, but the initializer mentions b, so we were recursing
> infinitely. But if we're interested in the address, we don't care
> about the value; we already handle that appropriately in the constexpr
> code, this patch updates value_dependent_expression_p accordingly.
I've been uneasy about this approach, since it isn't necessarily true
that we don't care about the value; we might indirect later to get
back to the value. So instead, this patch sets a flag to indicate a
constant variable with a dependent initializer.
The first patch is after reverting the other patch; the second is the
combination.
I also noticed that type_dependent_init_p is unnecessary since
type-dependence implies value-dependence.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit 18e711b75363ec2f304ee8fc162efea968f8f8af
Author: Jason Merrill <ja...@redhat.com>
Date: Fri Dec 8 07:45:02 2017 -0500
PR c++/82115 - ICE with variable initialized with its own address.
* cp-tree.h (struct lang_decl_base): Add dependent_init_p.
(DECL_DEPENDENT_INIT_P, SET_DECL_DEPENDENT_INIT_P): New.
* decl.c (cp_finish_decl): Set it.
(duplicate_decls): Copy it.
* pt.c (tsubst_decl): Clear it.
(value_dependent_expression_p): Check it.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 736c4844bcf..a7acf49986f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -2449,7 +2449,8 @@ struct GTY(()) lang_decl_base {
unsigned u2sel : 1;
unsigned concept_p : 1; /* applies to vars and functions */
unsigned var_declared_inline_p : 1; /* var */
- /* 2 spare bits */
+ unsigned dependent_init_p : 1; /* var */
+ /* 1 spare bit */
};
/* True for DECL codes which have template info and access. */
@@ -3879,6 +3880,13 @@ more_aggr_init_expr_args_p (const
aggr_init_expr_arg_iterator *iter)
(DECL_LANG_SPECIFIC (VAR_DECL_CHECK (NODE))->u.base.var_declared_inline_p \
= true)
+/* True if NODE is a variable with a value-dependent initializer. */
+#define DECL_DEPENDENT_INIT_P(NODE) \
+ (DECL_LANG_SPECIFIC (VAR_DECL_CHECK (NODE)) \
+ && DECL_LANG_SPECIFIC (NODE)->u.base.dependent_init_p)
+#define SET_DECL_DEPENDENT_INIT_P(NODE, X) \
+ (DECL_LANG_SPECIFIC (VAR_DECL_CHECK (NODE))->u.base.dependent_init_p = (X))
+
/* Nonzero if NODE is an artificial VAR_DECL for a C++17 structured binding
declaration or one of VAR_DECLs for the user identifiers in it. */
#define DECL_DECOMPOSITION_P(NODE) \
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 99b22dc878c..3601fa117c7 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2120,6 +2120,8 @@ next_arg:;
DECL_INITIALIZED_P (newdecl) |= DECL_INITIALIZED_P (olddecl);
DECL_NONTRIVIALLY_INITIALIZED_P (newdecl)
|= DECL_NONTRIVIALLY_INITIALIZED_P (olddecl);
+ if (DECL_DEPENDENT_INIT_P (olddecl))
+ SET_DECL_DEPENDENT_INIT_P (newdecl, true);
DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (newdecl)
|= DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (olddecl);
if (DECL_CLASS_SCOPE_P (olddecl))
@@ -6910,14 +6912,18 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
then it can be used in future constant expressions, so its value
must be available. */
+ bool dep_init = false;
+
if (!VAR_P (decl) || type_dependent_p)
/* We can't do anything if the decl has dependent type. */;
+ else if (!init && is_concept_var (decl))
+ error ("variable concept has no initializer");
else if (init
&& init_const_expr_p
&& TREE_CODE (type) != REFERENCE_TYPE
&& decl_maybe_constant_var_p (decl)
- && !type_dependent_init_p (init)
- && !value_dependent_init_p (init))
+ && !(dep_init = (type_dependent_init_p (init)
+ || value_dependent_init_p (init))))
{
/* This variable seems to be a non-dependent constant, so process
its initializer. If check_initializer returns non-null the
@@ -6929,8 +6935,6 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
init = NULL_TREE;
release_tree_vector (cleanups);
}
- else if (!init && is_concept_var (decl))
- error ("variable concept has no initializer");
else if (!DECL_PRETTY_FUNCTION_P (decl))
{
/* Deduce array size even if the initializer is dependent. */
@@ -6944,6 +6948,11 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
if (init)
DECL_INITIAL (decl) = init;
+ if (dep_init)
+ {
+ retrofit_lang_decl (decl);
+ SET_DECL_DEPENDENT_INIT_P (decl, true);
+ }
return;
}
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 8cb90dca761..b5be9807ea9 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -13135,6 +13135,9 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
DECL_SIZE (r) = DECL_SIZE_UNIT (r) = 0;
if (VAR_P (r))
{
+ if (DECL_LANG_SPECIFIC (r))
+ SET_DECL_DEPENDENT_INIT_P (r, false);
+
SET_DECL_MODE (r, VOIDmode);
/* Possibly limit visibility based on template args. */
@@ -23960,17 +23963,10 @@ value_dependent_expression_p (tree expression)
case VAR_DECL:
/* A constant with literal type and is initialized
- with an expression that is value-dependent.
-
- Note that a non-dependent parenthesized initializer will have
- already been replaced with its constant value, so if we see
- a TREE_LIST it must be dependent. */
- if (DECL_INITIAL (expression)
- && decl_constant_var_p (expression)
- && (TREE_CODE (DECL_INITIAL (expression)) == TREE_LIST
- /* cp_finish_decl doesn't fold reference initializers. */
- || TREE_CODE (TREE_TYPE (expression)) == REFERENCE_TYPE
- || value_dependent_expression_p (DECL_INITIAL (expression))))
+ with an expression that is value-dependent. */
+ if (DECL_DEPENDENT_INIT_P (expression)
+ /* FIXME cp_finish_decl doesn't fold reference initializers. */
+ || TREE_CODE (TREE_TYPE (expression)) == REFERENCE_TYPE)
return true;
if (DECL_HAS_VALUE_EXPR_P (expression))
{
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
index 96f1d18146a..32a10af49a6 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
@@ -12,3 +12,8 @@ struct B : A
constexpr B b (&b.u);
template < typename > void foo () { b; }
+
+template < typename T> void foo2 () {
+ constexpr B b2 = &b2.u;
+ b2;
+}
commit d3b6bd81a9f879d5aae72ce74fce6ffddd28a31f
Author: Jason Merrill <ja...@redhat.com>
Date: Fri Dec 8 07:45:02 2017 -0500
PR c++/82115 - ICE with variable initialized with its own address.
* cp-tree.h (struct lang_decl_base): Add dependent_init_p.
(DECL_DEPENDENT_INIT_P, SET_DECL_DEPENDENT_INIT_P): New.
* decl.c (cp_finish_decl): Set it.
(duplicate_decls): Copy it.
* pt.c (tsubst_decl): Clear it.
(value_dependent_expression_p): Check it.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 708d172bf61..a7acf49986f 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -2449,7 +2449,8 @@ struct GTY(()) lang_decl_base {
unsigned u2sel : 1;
unsigned concept_p : 1; /* applies to vars and functions */
unsigned var_declared_inline_p : 1; /* var */
- /* 2 spare bits */
+ unsigned dependent_init_p : 1; /* var */
+ /* 1 spare bit */
};
/* True for DECL codes which have template info and access. */
@@ -3879,6 +3880,13 @@ more_aggr_init_expr_args_p (const
aggr_init_expr_arg_iterator *iter)
(DECL_LANG_SPECIFIC (VAR_DECL_CHECK (NODE))->u.base.var_declared_inline_p \
= true)
+/* True if NODE is a variable with a value-dependent initializer. */
+#define DECL_DEPENDENT_INIT_P(NODE) \
+ (DECL_LANG_SPECIFIC (VAR_DECL_CHECK (NODE)) \
+ && DECL_LANG_SPECIFIC (NODE)->u.base.dependent_init_p)
+#define SET_DECL_DEPENDENT_INIT_P(NODE, X) \
+ (DECL_LANG_SPECIFIC (VAR_DECL_CHECK (NODE))->u.base.dependent_init_p = (X))
+
/* Nonzero if NODE is an artificial VAR_DECL for a C++17 structured binding
declaration or one of VAR_DECLs for the user identifiers in it. */
#define DECL_DECOMPOSITION_P(NODE) \
@@ -6542,7 +6550,7 @@ extern bool type_dependent_object_expression_p (tree);
extern bool any_type_dependent_arguments_p (const vec<tree, va_gc> *);
extern bool any_type_dependent_elements_p (const_tree);
extern bool type_dependent_expression_p_push (tree);
-extern bool value_dependent_expression_p (tree, bool = false);
+extern bool value_dependent_expression_p (tree);
extern bool instantiation_dependent_expression_p (tree);
extern bool instantiation_dependent_uneval_expression_p (tree);
extern bool any_value_dependent_elements_p (const_tree);
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 99b22dc878c..3601fa117c7 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -2120,6 +2120,8 @@ next_arg:;
DECL_INITIALIZED_P (newdecl) |= DECL_INITIALIZED_P (olddecl);
DECL_NONTRIVIALLY_INITIALIZED_P (newdecl)
|= DECL_NONTRIVIALLY_INITIALIZED_P (olddecl);
+ if (DECL_DEPENDENT_INIT_P (olddecl))
+ SET_DECL_DEPENDENT_INIT_P (newdecl, true);
DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (newdecl)
|= DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (olddecl);
if (DECL_CLASS_SCOPE_P (olddecl))
@@ -6910,14 +6912,18 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
then it can be used in future constant expressions, so its value
must be available. */
+ bool dep_init = false;
+
if (!VAR_P (decl) || type_dependent_p)
/* We can't do anything if the decl has dependent type. */;
+ else if (!init && is_concept_var (decl))
+ error ("variable concept has no initializer");
else if (init
&& init_const_expr_p
&& TREE_CODE (type) != REFERENCE_TYPE
&& decl_maybe_constant_var_p (decl)
- && !type_dependent_init_p (init)
- && !value_dependent_init_p (init))
+ && !(dep_init = (type_dependent_init_p (init)
+ || value_dependent_init_p (init))))
{
/* This variable seems to be a non-dependent constant, so process
its initializer. If check_initializer returns non-null the
@@ -6929,8 +6935,6 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
init = NULL_TREE;
release_tree_vector (cleanups);
}
- else if (!init && is_concept_var (decl))
- error ("variable concept has no initializer");
else if (!DECL_PRETTY_FUNCTION_P (decl))
{
/* Deduce array size even if the initializer is dependent. */
@@ -6944,6 +6948,11 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
if (init)
DECL_INITIAL (decl) = init;
+ if (dep_init)
+ {
+ retrofit_lang_decl (decl);
+ SET_DECL_DEPENDENT_INIT_P (decl, true);
+ }
return;
}
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 0cf6509c247..b5be9807ea9 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -13135,6 +13135,9 @@ tsubst_decl (tree t, tree args, tsubst_flags_t complain)
DECL_SIZE (r) = DECL_SIZE_UNIT (r) = 0;
if (VAR_P (r))
{
+ if (DECL_LANG_SPECIFIC (r))
+ SET_DECL_DEPENDENT_INIT_P (r, false);
+
SET_DECL_MODE (r, VOIDmode);
/* Possibly limit visibility based on template args. */
@@ -23922,7 +23925,7 @@ instantiation_dependent_scope_ref_p (tree t)
can be tested for value dependence. */
bool
-value_dependent_expression_p (tree expression, bool lval /* = false */)
+value_dependent_expression_p (tree expression)
{
if (!processing_template_decl || expression == NULL_TREE)
return false;
@@ -23956,28 +23959,19 @@ value_dependent_expression_p (tree expression, bool
lval /* = false */)
/* A non-type template parm. */
if (DECL_TEMPLATE_PARM_P (expression))
return true;
- gcc_checking_assert (!lval);
return value_dependent_expression_p (DECL_INITIAL (expression));
case VAR_DECL:
/* A constant with literal type and is initialized
- with an expression that is value-dependent.
-
- Note that a non-dependent parenthesized initializer will have
- already been replaced with its constant value, so if we see
- a TREE_LIST it must be dependent. */
- if (!lval
- && DECL_INITIAL (expression)
- && decl_constant_var_p (expression)
- && (TREE_CODE (DECL_INITIAL (expression)) == TREE_LIST
- /* cp_finish_decl doesn't fold reference initializers. */
- || TREE_CODE (TREE_TYPE (expression)) == REFERENCE_TYPE
- || value_dependent_expression_p (DECL_INITIAL (expression))))
+ with an expression that is value-dependent. */
+ if (DECL_DEPENDENT_INIT_P (expression)
+ /* FIXME cp_finish_decl doesn't fold reference initializers. */
+ || TREE_CODE (TREE_TYPE (expression)) == REFERENCE_TYPE)
return true;
if (DECL_HAS_VALUE_EXPR_P (expression))
{
tree value_expr = DECL_VALUE_EXPR (expression);
- if (value_dependent_expression_p (value_expr, lval))
+ if (value_dependent_expression_p (value_expr))
return true;
}
return false;
@@ -24013,7 +24007,7 @@ value_dependent_expression_p (tree expression, bool
lval /* = false */)
if (TREE_CODE (expression) == TREE_LIST)
return any_value_dependent_elements_p (expression);
- return value_dependent_expression_p (expression, lval);
+ return value_dependent_expression_p (expression);
}
case SIZEOF_EXPR:
@@ -24047,7 +24041,7 @@ value_dependent_expression_p (tree expression, bool
lval /* = false */)
return instantiation_dependent_scope_ref_p (expression);
case COMPONENT_REF:
- return (value_dependent_expression_p (TREE_OPERAND (expression, 0), lval)
+ return (value_dependent_expression_p (TREE_OPERAND (expression, 0))
|| value_dependent_expression_p (TREE_OPERAND (expression, 1)));
case NONTYPE_ARGUMENT_PACK:
@@ -24095,7 +24089,7 @@ value_dependent_expression_p (tree expression, bool
lval /* = false */)
case ADDR_EXPR:
{
tree op = TREE_OPERAND (expression, 0);
- return (value_dependent_expression_p (op, true)
+ return (value_dependent_expression_p (op)
|| has_value_dependent_address (op));
}
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
b/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
index 96f1d18146a..32a10af49a6 100644
--- a/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-self1.C
@@ -12,3 +12,8 @@ struct B : A
constexpr B b (&b.u);
template < typename > void foo () { b; }
+
+template < typename T> void foo2 () {
+ constexpr B b2 = &b2.u;
+ b2;
+}
commit eaf85e22f4f3e7b78e68e2cfac5c49eb650e06dd
Author: Jason Merrill <ja...@redhat.com>
Date: Fri Dec 8 16:05:32 2017 -0500
Remove type_dependent_init_p.
* decl.c (value_dependent_init_p): Check the type of a CONSTRUCTOR.
(type_dependent_init_p): Remove.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 3601fa117c7..445c23c5dac 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6644,38 +6644,6 @@ initialize_artificial_var (tree decl,
vec<constructor_elt, va_gc> *v)
}
/* INIT is the initializer for a variable, as represented by the
- parser. Returns true iff INIT is type-dependent. */
-
-static bool
-type_dependent_init_p (tree init)
-{
- if (TREE_CODE (init) == TREE_LIST)
- /* A parenthesized initializer, e.g.: int i (3, 2); ? */
- return any_type_dependent_elements_p (init);
- else if (TREE_CODE (init) == CONSTRUCTOR)
- /* A brace-enclosed initializer, e.g.: int i = { 3 }; ? */
- {
- if (dependent_type_p (TREE_TYPE (init)))
- return true;
-
- vec<constructor_elt, va_gc> *elts;
- size_t nelts;
- size_t i;
-
- elts = CONSTRUCTOR_ELTS (init);
- nelts = vec_safe_length (elts);
- for (i = 0; i < nelts; ++i)
- if (type_dependent_init_p ((*elts)[i].value))
- return true;
- }
- else
- /* It must be a simple expression, e.g., int i = 3; */
- return type_dependent_expression_p (init);
-
- return false;
-}
-
-/* INIT is the initializer for a variable, as represented by the
parser. Returns true iff INIT is value-dependent. */
static bool
@@ -6687,6 +6655,9 @@ value_dependent_init_p (tree init)
else if (TREE_CODE (init) == CONSTRUCTOR)
/* A brace-enclosed initializer, e.g.: int i = { 3 }; ? */
{
+ if (dependent_type_p (TREE_TYPE (init)))
+ return true;
+
vec<constructor_elt, va_gc> *elts;
size_t nelts;
size_t i;
@@ -6922,8 +6893,7 @@ cp_finish_decl (tree decl, tree init, bool
init_const_expr_p,
&& init_const_expr_p
&& TREE_CODE (type) != REFERENCE_TYPE
&& decl_maybe_constant_var_p (decl)
- && !(dep_init = (type_dependent_init_p (init)
- || value_dependent_init_p (init))))
+ && !(dep_init = value_dependent_init_p (init)))
{
/* This variable seems to be a non-dependent constant, so process
its initializer. If check_initializer returns non-null the
