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author | Patrick Palka <ppalka@redhat.com> | 2020-05-29 09:44:09 -0400 |
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committer | Patrick Palka <ppalka@redhat.com> | 2020-05-29 09:44:09 -0400 |
commit | e069285cdf457cc85070e522380c4e25b0d2ed25 (patch) | |
tree | 8995b8d5e7269134952bc3393cbdc82250e983d1 /gcc/cp | |
parent | c92716b2b1d117a803775a2e2336b751050ff7c2 (diff) | |
download | gcc-e069285cdf457cc85070e522380c4e25b0d2ed25.zip gcc-e069285cdf457cc85070e522380c4e25b0d2ed25.tar.gz gcc-e069285cdf457cc85070e522380c4e25b0d2ed25.tar.bz2 |
c++: constexpr ctor with RANGE_EXPR index [PR95241]
In the testcase below, the CONSTRUCTOR for 'field' contains a RANGE_EXPR
index:
{{aggr_init_expr<...>, [1...2]={.off=1}}}
but get_or_insert_ctor_field isn't prepared to handle looking up a
RANGE_EXPR index.
This patch adds limited support to get_or_insert_ctor_field for looking
up a RANGE_EXPR index. The limited scope of this patch should make it
more suitable for backporting, and more extensive support would be
needed only to handle self-modifying CONSTRUCTORs that contain a
RANGE_EXPR index, but I haven't yet been able to come up with a testcase
that actually creates such a CONSTRUCTOR.
gcc/cp/ChangeLog:
PR c++/95241
* constexpr.c (get_or_insert_ctor_field): Add limited support
for RANGE_EXPR index lookups.
gcc/testsuite/ChangeLog:
PR c++/95241
* g++.dg/cpp0x/constexpr-array25.C: New test.
Diffstat (limited to 'gcc/cp')
-rw-r--r-- | gcc/cp/constexpr.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 4b1f92f..959f025 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -3299,6 +3299,22 @@ get_or_insert_ctor_field (tree ctor, tree index, int pos_hint = -1) } else if (TREE_CODE (type) == ARRAY_TYPE || TREE_CODE (type) == VECTOR_TYPE) { + if (TREE_CODE (index) == RANGE_EXPR) + { + /* Support for RANGE_EXPR index lookups is currently limited to + accessing an existing element via POS_HINT, or appending a new + element to the end of CTOR. ??? Support for other access + patterns may also be needed. */ + vec<constructor_elt, va_gc> *elts = CONSTRUCTOR_ELTS (ctor); + if (vec_safe_length (elts)) + { + tree lo = TREE_OPERAND (index, 0); + gcc_assert (array_index_cmp (elts->last().index, lo) < 0); + } + CONSTRUCTOR_APPEND_ELT (elts, index, NULL_TREE); + return &elts->last(); + } + HOST_WIDE_INT i = find_array_ctor_elt (ctor, index, /*insert*/true); gcc_assert (i >= 0); constructor_elt *cep = CONSTRUCTOR_ELT (ctor, i); |