diff options
Diffstat (limited to 'gcc/cp/tree.c')
| -rw-r--r-- | gcc/cp/tree.c | 51 |
1 files changed, 31 insertions, 20 deletions
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c index 236180de7fd..2b541cd5bd5 100644 --- a/gcc/cp/tree.c +++ b/gcc/cp/tree.c @@ -3283,8 +3283,8 @@ stabilize_expr (tree exp, tree* initp) init_expr = NULL_TREE; else if (VOID_TYPE_P (TREE_TYPE (exp))) { - *initp = exp; - return void_zero_node; + init_expr = exp; + exp = void_zero_node; } /* There are no expressions with REFERENCE_TYPE, but there can be call arguments with such a type; just treat it as a pointer. */ @@ -3389,7 +3389,7 @@ stabilize_aggr_init (tree call, tree *initp) takes care not to introduce additional temporaries. Returns TRUE iff the expression was successfully pre-evaluated, - i.e., if INIT is now side-effect free, except for, possible, a + i.e., if INIT is now side-effect free, except for, possibly, a single call to a constructor. */ bool @@ -3402,21 +3402,37 @@ stabilize_init (tree init, tree *initp) if (t == error_mark_node || processing_template_decl) return true; - if (TREE_CODE (t) == INIT_EXPR - && TREE_CODE (TREE_OPERAND (t, 1)) != TARGET_EXPR - && TREE_CODE (TREE_OPERAND (t, 1)) != CONSTRUCTOR - && TREE_CODE (TREE_OPERAND (t, 1)) != AGGR_INIT_EXPR) - { - TREE_OPERAND (t, 1) = stabilize_expr (TREE_OPERAND (t, 1), initp); - return true; - } - if (TREE_CODE (t) == INIT_EXPR) t = TREE_OPERAND (t, 1); if (TREE_CODE (t) == TARGET_EXPR) t = TARGET_EXPR_INITIAL (t); - if (TREE_CODE (t) == COMPOUND_EXPR) - t = expr_last (t); + + /* If the RHS can be stabilized without breaking copy elision, stabilize + it. We specifically don't stabilize class prvalues here because that + would mean an extra copy, but they might be stabilized below. */ + if (TREE_CODE (init) == INIT_EXPR + && TREE_CODE (t) != CONSTRUCTOR + && TREE_CODE (t) != AGGR_INIT_EXPR + && (SCALAR_TYPE_P (TREE_TYPE (t)) + || lvalue_or_rvalue_with_address_p (t))) + { + TREE_OPERAND (init, 1) = stabilize_expr (t, initp); + return true; + } + + if (TREE_CODE (t) == COMPOUND_EXPR + && TREE_CODE (init) == INIT_EXPR) + { + tree last = expr_last (t); + /* Handle stabilizing the EMPTY_CLASS_EXPR pattern. */ + if (!TREE_SIDE_EFFECTS (last)) + { + *initp = t; + TREE_OPERAND (init, 1) = last; + return true; + } + } + if (TREE_CODE (t) == CONSTRUCTOR) { /* Aggregate initialization: stabilize each of the field @@ -3439,11 +3455,6 @@ stabilize_init (tree init, tree *initp) return good; } - /* If the initializer is a COND_EXPR, we can't preevaluate - anything. */ - if (TREE_CODE (t) == COND_EXPR) - return false; - if (TREE_CODE (t) == CALL_EXPR) { stabilize_call (t, initp); @@ -3458,7 +3469,7 @@ stabilize_init (tree init, tree *initp) /* The initialization is being performed via a bitwise copy -- and the item copied may have side effects. */ - return TREE_SIDE_EFFECTS (init); + return !TREE_SIDE_EFFECTS (init); } /* Like "fold", but should be used whenever we might be processing the |