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author | Patrick Palka <ppalka@redhat.com> | 2020-10-07 10:49:00 -0400 |
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committer | Patrick Palka <ppalka@redhat.com> | 2020-10-07 10:49:00 -0400 |
commit | 592fe221735bdaa375b1834dd49ce125d0b600d8 (patch) | |
tree | 0dfbac3922630cfb34eaecf8d06ff87b1e2ac6f3 | |
parent | 4e9213027587b807ca7e4bbde706b19102342d37 (diff) | |
download | gcc-592fe221735bdaa375b1834dd49ce125d0b600d8.zip gcc-592fe221735bdaa375b1834dd49ce125d0b600d8.tar.gz gcc-592fe221735bdaa375b1834dd49ce125d0b600d8.tar.bz2 |
c++: Distinguish alignof and __alignof__ in cp_tree_equal [PR97273]
cp_tree_equal currently considers alignof the same as __alignof__, but
these operators are semantically different ever since r8-7957. In the
testcase below, this causes the second static_assert to fail on targets
where alignof(double) != __alignof__(double) because the specialization
table (which uses cp_tree_equal as its equality predicate) conflates the
two dependent specializations integral_constant<__alignof__(T)> and
integral_constant<alignof(T)>.
This patch makes cp_tree_equal distinguish between these two operators
by inspecting the ALIGNOF_EXPR_STD_P flag.
gcc/cp/ChangeLog:
PR c++/88115
PR libstdc++/97273
* tree.c (cp_tree_equal) <case ALIGNOF_EXPR>: Return false if
ALIGNOF_EXPR_STD_P differ.
gcc/testsuite/ChangeLog:
PR c++/88115
PR libstdc++/97273
* g++.dg/template/alignof3.C: New test.
-rw-r--r-- | gcc/cp/tree.c | 2 | ||||
-rw-r--r-- | gcc/testsuite/g++.dg/template/alignof3.C | 13 |
2 files changed, 15 insertions, 0 deletions
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c index 074fa0c..9bc37ac 100644 --- a/gcc/cp/tree.c +++ b/gcc/cp/tree.c @@ -3803,6 +3803,8 @@ cp_tree_equal (tree t1, tree t2) if (SIZEOF_EXPR_TYPE_P (t2)) o2 = TREE_TYPE (o2); } + else if (ALIGNOF_EXPR_STD_P (t1) != ALIGNOF_EXPR_STD_P (t2)) + return false; if (TREE_CODE (o1) != TREE_CODE (o2)) return false; diff --git a/gcc/testsuite/g++.dg/template/alignof3.C b/gcc/testsuite/g++.dg/template/alignof3.C new file mode 100644 index 0000000..e573727 --- /dev/null +++ b/gcc/testsuite/g++.dg/template/alignof3.C @@ -0,0 +1,13 @@ +// PR c++/88115 +// { dg-do compile { target c++11 } } + +template<int __v> +struct integral_constant { + static constexpr int value = __v; +}; + +template <class T> using StdAlignOf = integral_constant<alignof(T)>; +template <class T> using GCCAlignOf = integral_constant<__alignof__(T)>; + +static_assert(StdAlignOf<double>::value == alignof(double), ""); +static_assert(GCCAlignOf<double>::value == __alignof__(double), ""); |