Tested x86_64-pc-linux-gnu, applying to trunk.
-- >8 --
I was wondering how lvalue_kind handles VIEW_CONVERT_EXPR; in cases where
the type actually changes, it should have the same prvalue->xvalue effect as
ARRAY_REF, since we need to materialize a temporary to get an object we can
reinterpret as another type.
Currently this only fires on builtin-shufflevector-3.c, where we use
VIEW_CONVERT_EXPR to reinterpret a vector as an array.
REALPART_EXPR and IMAGPART_EXPR should also be treated like COMPONENT_REF.
PREINCREMENT_EXPR and PREDECREMENT_EXPR should only be applied to glvalues,
but if for some reason they were applied to a prvalue this would be correct.
TRY_CATCH_EXPR around a prvalue is also questionable, but this is the right
handling.
gcc/cp/ChangeLog:
* tree.cc (lvalue_kind) [VIEW_CONVERT_EXPR]: Change prvalue to
xvalue.
---
gcc/cp/tree.cc | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/gcc/cp/tree.cc b/gcc/cp/tree.cc
index aa9c1b7d8f9..6d968a2af11 100644
--- a/gcc/cp/tree.cc
+++ b/gcc/cp/tree.cc
@@ -104,7 +104,17 @@ lvalue_kind (const_tree ref)
case REALPART_EXPR:
case IMAGPART_EXPR:
case VIEW_CONVERT_EXPR:
- return lvalue_kind (TREE_OPERAND (ref, 0));
+ op1_lvalue_kind = lvalue_kind (TREE_OPERAND (ref, 0));
+ /* As for ARRAY_REF and COMPONENT_REF, these codes turn a class prvalue
+ into an xvalue: we need to materialize the temporary before we mess
+ with it. Except VIEW_CONVERT_EXPR that doesn't actually change the
+ type, as in location wrapper and REF_PARENTHESIZED_P. */
+ if (op1_lvalue_kind == clk_class
+ && !(TREE_CODE (ref) == VIEW_CONVERT_EXPR
+ && (same_type_ignoring_top_level_qualifiers_p
+ (TREE_TYPE (ref), TREE_TYPE (TREE_OPERAND (ref, 0))))))
+ return clk_rvalueref;
+ return op1_lvalue_kind;
case ARRAY_REF:
{
base-commit: 7d935cdd1a6772699ec0ab4f93711928ca4d30a1
--
2.31.1
