| Message ID | 20220128010209.586323-1-polacek@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | c++: ICE with auto[] and VLA [PR102414] | expand |
On 1/27/22 20:02, Marek Polacek wrote: > Here we ICE in unify_array_domain when we're trying to deduce the type > of an array, as in > > auto(*p)[i] = (int(*)[i])0; > > but unify_array_domain doesn't arbitrarily complex bounds. Another > test is, e.g., > > auto (*b)[0/0] = &a; > > where the type of the array is > > <<< Unknown tree: template_type_parm >>>[0:(sizetype) ((ssizetype) (0 / 0) - 1)] > > It seems to me that we need not handle these. > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > PR c++/102414 > PR c++/101874 > > gcc/cp/ChangeLog: > > * decl.cc (create_array_type_for_decl): Use template_placeholder_p. > Sorry on a variable-length array of auto. > > gcc/testsuite/ChangeLog: > > * g++.dg/cpp23/auto-array3.C: New test. > * g++.dg/cpp23/auto-array4.C: New test. > --- > gcc/cp/decl.cc | 14 +++++++++++--- > gcc/testsuite/g++.dg/cpp23/auto-array3.C | 17 +++++++++++++++++ > gcc/testsuite/g++.dg/cpp23/auto-array4.C | 10 ++++++++++ > 3 files changed, 38 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/g++.dg/cpp23/auto-array3.C > create mode 100644 gcc/testsuite/g++.dg/cpp23/auto-array4.C > > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc > index 10e6956117e..4ba8bf3e8a9 100644 > --- a/gcc/cp/decl.cc > +++ b/gcc/cp/decl.cc > @@ -11089,7 +11089,7 @@ create_array_type_for_decl (tree name, tree type, tree size, location_t loc) > > /* [dcl.type.class.deduct] prohibits forming an array of placeholder > for a deduced class type. */ > - if (is_auto (type) && CLASS_PLACEHOLDER_TEMPLATE (type)) > + if (template_placeholder_p (type)) > { > if (name) > error_at (loc, "%qD declared as array of template placeholder " > @@ -11159,8 +11159,16 @@ create_array_type_for_decl (tree name, tree type, tree size, location_t loc) > > /* Figure out the index type for the array. */ > if (size) > - itype = compute_array_index_type_loc (loc, name, size, > - tf_warning_or_error); > + { > + itype = compute_array_index_type_loc (loc, name, size, > + tf_warning_or_error); > + if (type_uses_auto (type) > + && !TREE_CONSTANT (maybe_constant_value (size))) Maybe variably_modified_type_p (itype)? > + { > + sorry_at (loc, "variable-length array of %<auto%>"); > + return error_mark_node; > + } > + } > > return build_cplus_array_type (type, itype); > } > diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array3.C b/gcc/testsuite/g++.dg/cpp23/auto-array3.C > new file mode 100644 > index 00000000000..e383a17d0ee > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp23/auto-array3.C > @@ -0,0 +1,17 @@ > +// PR c++/102414 > +// { dg-do compile { target c++11 } } > +// { dg-options "" } > + > +constexpr int sz () { return 3; } > + > +void f () > +{ > + int a[3]; > + auto (*a1)[0/0] = &a; // { dg-message "variable-length array of .auto." } > +// { dg-warning "division by zero" "" { target *-*-* } .-1 } Let's move the error into the other testcase? > + const int N = 3; > + auto (*a2)[N] = &a; > + constexpr int M = 3; > + auto (*a3)[M] = &a; > + auto (*a4)[sz()] = &a; > +} > diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array4.C b/gcc/testsuite/g++.dg/cpp23/auto-array4.C > new file mode 100644 > index 00000000000..4819472a9ac > --- /dev/null > +++ b/gcc/testsuite/g++.dg/cpp23/auto-array4.C > @@ -0,0 +1,10 @@ > +// PR c++/101874 > +// { dg-do compile { target c++11 } } > +// { dg-options "" } > + > +void > +f (int i) > +{ > + auto x[i] = { 0 }; // { dg-message "variable-length array of .auto." } > + auto(*p)[i] = (int(*)[i])0; // { dg-message "variable-length array of .auto." } > +} > > base-commit: 99f17e996f21d0ed64c36ed1e52977b705143522
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index 10e6956117e..4ba8bf3e8a9 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -11089,7 +11089,7 @@ create_array_type_for_decl (tree name, tree type, tree size, location_t loc) /* [dcl.type.class.deduct] prohibits forming an array of placeholder for a deduced class type. */ - if (is_auto (type) && CLASS_PLACEHOLDER_TEMPLATE (type)) + if (template_placeholder_p (type)) { if (name) error_at (loc, "%qD declared as array of template placeholder " @@ -11159,8 +11159,16 @@ create_array_type_for_decl (tree name, tree type, tree size, location_t loc) /* Figure out the index type for the array. */ if (size) - itype = compute_array_index_type_loc (loc, name, size, - tf_warning_or_error); + { + itype = compute_array_index_type_loc (loc, name, size, + tf_warning_or_error); + if (type_uses_auto (type) + && !TREE_CONSTANT (maybe_constant_value (size))) + { + sorry_at (loc, "variable-length array of %<auto%>"); + return error_mark_node; + } + } return build_cplus_array_type (type, itype); } diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array3.C b/gcc/testsuite/g++.dg/cpp23/auto-array3.C new file mode 100644 index 00000000000..e383a17d0ee --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp23/auto-array3.C @@ -0,0 +1,17 @@ +// PR c++/102414 +// { dg-do compile { target c++11 } } +// { dg-options "" } + +constexpr int sz () { return 3; } + +void f () +{ + int a[3]; + auto (*a1)[0/0] = &a; // { dg-message "variable-length array of .auto." } +// { dg-warning "division by zero" "" { target *-*-* } .-1 } + const int N = 3; + auto (*a2)[N] = &a; + constexpr int M = 3; + auto (*a3)[M] = &a; + auto (*a4)[sz()] = &a; +} diff --git a/gcc/testsuite/g++.dg/cpp23/auto-array4.C b/gcc/testsuite/g++.dg/cpp23/auto-array4.C new file mode 100644 index 00000000000..4819472a9ac --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp23/auto-array4.C @@ -0,0 +1,10 @@ +// PR c++/101874 +// { dg-do compile { target c++11 } } +// { dg-options "" } + +void +f (int i) +{ + auto x[i] = { 0 }; // { dg-message "variable-length array of .auto." } + auto(*p)[i] = (int(*)[i])0; // { dg-message "variable-length array of .auto." } +}