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authorJason Merrill <jason@redhat.com>2023-12-19 16:12:02 -0500
committerJason Merrill <jason@redhat.com>2023-12-20 12:30:13 -0500
commit8dfc52a75d4d6c8be1c61b4aa831b1812b14a10e (patch)
tree1ee1ac2b1773a0a283b218e8bff61fd443a9c96b /gcc
parenta3ff76278efe006dc0b50249c8e5baf565bff56b (diff)
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c++: xvalue array subscript [PR103185]
Normally we handle xvalue array subscripting with ARRAY_REF, but in this case we weren't doing that because the operands were reversed. Handle that case better. PR c++/103185 gcc/cp/ChangeLog: * typeck.cc (cp_build_array_ref): Handle swapped operands. gcc/testsuite/ChangeLog: * g++.dg/cpp1z/array-prvalue2.C: New test. * g++.dg/cpp1z/eval-order3.C: Test swapped operands.
Diffstat (limited to 'gcc')
-rw-r--r--gcc/cp/typeck.cc16
-rw-r--r--gcc/testsuite/g++.dg/cpp1z/array-prvalue2.C5
-rw-r--r--gcc/testsuite/g++.dg/cpp1z/eval-order3.C5
3 files changed, 23 insertions, 3 deletions
diff --git a/gcc/cp/typeck.cc b/gcc/cp/typeck.cc
index a6e2f4e..1fe30fc 100644
--- a/gcc/cp/typeck.cc
+++ b/gcc/cp/typeck.cc
@@ -3932,13 +3932,14 @@ cp_build_indirect_ref (location_t loc, tree ptr, ref_operator errorstring,
If INDEX is of some user-defined type, it must be converted to
integer type. Otherwise, to make a compatible PLUS_EXPR, it
will inherit the type of the array, which will be some pointer type.
-
+
LOC is the location to use in building the array reference. */
tree
cp_build_array_ref (location_t loc, tree array, tree idx,
tsubst_flags_t complain)
{
+ tree first = NULL_TREE;
tree ret;
if (idx == 0)
@@ -3983,6 +3984,14 @@ cp_build_array_ref (location_t loc, tree array, tree idx,
bool non_lvalue = convert_vector_to_array_for_subscript (loc, &array, idx);
+ /* 0[array] */
+ if (TREE_CODE (TREE_TYPE (idx)) == ARRAY_TYPE)
+ {
+ std::swap (array, idx);
+ if (flag_strong_eval_order == 2 && TREE_SIDE_EFFECTS (array))
+ idx = first = save_expr (idx);
+ }
+
if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE)
{
tree rval, type;
@@ -4058,15 +4067,16 @@ cp_build_array_ref (location_t loc, tree array, tree idx,
protected_set_expr_location (ret, loc);
if (non_lvalue)
ret = non_lvalue_loc (loc, ret);
+ if (first)
+ ret = build2_loc (loc, COMPOUND_EXPR, TREE_TYPE (ret), first, ret);
return ret;
}
{
tree ar = cp_default_conversion (array, complain);
tree ind = cp_default_conversion (idx, complain);
- tree first = NULL_TREE;
- if (flag_strong_eval_order == 2 && TREE_SIDE_EFFECTS (ind))
+ if (!first && flag_strong_eval_order == 2 && TREE_SIDE_EFFECTS (ind))
ar = first = save_expr (ar);
/* Put the integer in IND to simplify error checking. */
diff --git a/gcc/testsuite/g++.dg/cpp1z/array-prvalue2.C b/gcc/testsuite/g++.dg/cpp1z/array-prvalue2.C
new file mode 100644
index 0000000..60a038c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/array-prvalue2.C
@@ -0,0 +1,5 @@
+// PR c++/103185
+// { dg-do compile { target c++11 } }
+
+using intarr = int[];
+static_assert(__is_same(decltype(0[intarr{0}]), int&&), "");
diff --git a/gcc/testsuite/g++.dg/cpp1z/eval-order3.C b/gcc/testsuite/g++.dg/cpp1z/eval-order3.C
index 5773591..897cdef 100644
--- a/gcc/testsuite/g++.dg/cpp1z/eval-order3.C
+++ b/gcc/testsuite/g++.dg/cpp1z/eval-order3.C
@@ -166,6 +166,11 @@ void g()
ip(24)[f(25)-25] = 0;
last=0;
+ // even with swapped operands
+ (f(20)-20)[afn(21)].memfn(f(22),23);
+ (f(24)-24)[ip(25)] = 0;
+ last=0;
+
// a << b
aref(24) << f(25);
iref(26) << f(27);