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author | Jason Merrill <jason@redhat.com> | 2016-01-14 10:32:31 -0500 |
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committer | Jason Merrill <jason@gcc.gnu.org> | 2016-01-14 10:32:31 -0500 |
commit | a7ccb9e72266f4cd82801166008b0b98cd25c773 (patch) | |
tree | ca8051f9263fb4a37987b5467c7657252947ee71 | |
parent | 73e48cb322152bf504ced8694fa748544ecaa6eb (diff) | |
download | gcc-a7ccb9e72266f4cd82801166008b0b98cd25c773.zip gcc-a7ccb9e72266f4cd82801166008b0b98cd25c773.tar.gz gcc-a7ccb9e72266f4cd82801166008b0b98cd25c773.tar.bz2 |
re PR c++/69261 (Copying char arrays during constexpr evaluation does not work reliably)
PR c++/69261
* constexpr.c (find_array_ctor_elt): Handle splitting RANGE_EXPR.
From-SVN: r232370
-rw-r--r-- | gcc/cp/ChangeLog | 5 | ||||
-rw-r--r-- | gcc/cp/constexpr.c | 47 | ||||
-rw-r--r-- | gcc/testsuite/g++.dg/cpp1y/constexpr-array2.C | 63 |
3 files changed, 113 insertions, 2 deletions
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog index 7230c71..54db540 100644 --- a/gcc/cp/ChangeLog +++ b/gcc/cp/ChangeLog @@ -1,3 +1,8 @@ +2016-01-14 Jason Merrill <jason@redhat.com> + + PR c++/69261 + * constexpr.c (find_array_ctor_elt): Handle splitting RANGE_EXPR. + 2016-01-12 Marek Polacek <polacek@redhat.com> PR c++/68979 diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c index 36a1e42..6ab4696 100644 --- a/gcc/cp/constexpr.c +++ b/gcc/cp/constexpr.c @@ -1725,14 +1725,57 @@ find_array_ctor_elt (tree ary, tree dindex, bool insert = false) while (begin != end) { unsigned HOST_WIDE_INT middle = (begin + end) / 2; + constructor_elt &elt = (*elts)[middle]; + tree idx = elt.index; - int cmp = array_index_cmp (dindex, (*elts)[middle].index); + int cmp = array_index_cmp (dindex, idx); if (cmp < 0) end = middle; else if (cmp > 0) begin = middle + 1; else - return middle; + { + if (insert && TREE_CODE (idx) == RANGE_EXPR) + { + /* We need to split the range. */ + constructor_elt e; + tree lo = TREE_OPERAND (idx, 0); + tree hi = TREE_OPERAND (idx, 1); + if (tree_int_cst_lt (lo, dindex)) + { + /* There are still some lower elts; shorten the range. */ + tree new_hi = int_const_binop (MINUS_EXPR, dindex, + size_one_node); + if (tree_int_cst_equal (lo, new_hi)) + /* Only one element left, no longer a range. */ + elt.index = lo; + else + TREE_OPERAND (idx, 1) = new_hi; + /* Append the element we want to insert. */ + ++middle; + e.index = dindex; + e.value = unshare_expr (elt.value); + vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle, e); + } + else + /* No lower elts, the range elt is now ours. */ + elt.index = dindex; + + if (tree_int_cst_lt (dindex, hi)) + { + /* There are still some higher elts; append a range. */ + tree new_lo = int_const_binop (PLUS_EXPR, dindex, + size_one_node); + if (tree_int_cst_equal (new_lo, hi)) + e.index = hi; + else + e.index = build2 (RANGE_EXPR, sizetype, new_lo, hi); + e.value = unshare_expr (elt.value); + vec_safe_insert (CONSTRUCTOR_ELTS (ary), middle+1, e); + } + } + return middle; + } } if (insert) diff --git a/gcc/testsuite/g++.dg/cpp1y/constexpr-array2.C b/gcc/testsuite/g++.dg/cpp1y/constexpr-array2.C new file mode 100644 index 0000000..71b3642 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp1y/constexpr-array2.C @@ -0,0 +1,63 @@ +// PR c++/69261 +// { dg-do run { target c++14 } } + +typedef __SIZE_TYPE__ size_t; + +template <size_t N> +struct S +{ + constexpr S() = default; + + template<size_t M> + constexpr S (char const (&d)[M]) : data { 0 } + { + static_assert (M <= N, "size!"); + for (size_t i = 0; i != M; i++) + data[i] = d[i]; + } + char data[N]; +}; + +template <int N> +constexpr S<N> +s (char const (&d)[N]) +{ + S<N> c {}; + for (size_t i = 0; i != N; i++) + c.data[i] = d[i]; + return c; +} + +template <size_t N, size_t M> +constexpr auto +concat (S<N> const& s1, S<M> const& s2) +{ + S<N+M-1> s (s1.data); + for (size_t i = 0; i != M; i++) + s.data[N + i - 1] = s2.data[i]; + return s; +} + +template <size_t N, size_t M> +constexpr auto +concat (char const (&x)[N], char const (&y)[M]) +{ + S<N+M-1> tmp { x }; + for (size_t i = 0; i != M; i++) + tmp.data[N+i-1] = y[i]; + return tmp; +} + +int +main () +{ + auto constexpr s1 = s ("bla"); + auto constexpr s2 = s ("blub"); + S<8> constexpr s1s2 = concat (s1, s2); + auto constexpr c = concat ("bla", "blub"); + if (__builtin_strcmp (s1.data, "bla") + || __builtin_strcmp (s2.data, "blub") + || __builtin_strcmp (s1s2.data, "blablub") + || __builtin_strcmp (c.data, "blablub")) + __builtin_abort (); +} |