diff options
Diffstat (limited to 'gcc/cp/constexpr.cc')
| -rw-r--r-- | gcc/cp/constexpr.cc | 42 |
1 files changed, 38 insertions, 4 deletions
diff --git a/gcc/cp/constexpr.cc b/gcc/cp/constexpr.cc index 61481c6..7078839 100644 --- a/gcc/cp/constexpr.cc +++ b/gcc/cp/constexpr.cc @@ -6413,7 +6413,8 @@ cxx_eval_store_expression (const constexpr_ctx *ctx, tree t, if (TREE_CLOBBER_P (init) && CLOBBER_KIND (init) < CLOBBER_OBJECT_END) - /* Only handle clobbers ending the lifetime of objects. */ + /* Only handle clobbers ending the lifetime of objects. + ??? We should probably set CONSTRUCTOR_NO_CLEARING. */ return void_node; /* First we figure out where we're storing to. */ @@ -9278,8 +9279,7 @@ cxx_eval_outermost_constant_expr (tree t, bool allow_non_constant, /* After verify_constant because reduced_constant_expression_p can unset CONSTRUCTOR_NO_CLEARING. */ - if (!non_constant_p - && TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_NO_CLEARING (r)) + if (TREE_CODE (r) == CONSTRUCTOR && CONSTRUCTOR_NO_CLEARING (r)) { if (!allow_non_constant) error ("%qE is not a constant expression because it refers to " @@ -9488,8 +9488,35 @@ tree maybe_constant_value (tree t, tree decl /* = NULL_TREE */, mce_value manifestly_const_eval /* = mce_unknown */) { + tree orig_t = t; tree r; + if (EXPR_P (t) && manifestly_const_eval == mce_unknown) + { + /* Look up each operand in the cv_cache first to see if we've already + reduced it, and reuse that result to avoid quadratic behavior if + we're called when building up a large expression. */ + int n = cp_tree_operand_length (t); + tree *ops = XALLOCAVEC (tree, n); + bool rebuild = false; + for (int i = 0; i < n; ++i) + { + ops[i] = TREE_OPERAND (t, i); + if (tree *cached = hash_map_safe_get (cv_cache, ops[i])) + if (*cached != ops[i]) + { + ops[i] = *cached; + rebuild = true; + } + } + if (rebuild) + { + t = copy_node (t); + for (int i = 0; i < n; ++i) + TREE_OPERAND (t, i) = ops[i]; + } + } + if (!is_nondependent_constant_expression (t)) { if (TREE_OVERFLOW_P (t) @@ -9507,6 +9534,10 @@ maybe_constant_value (tree t, tree decl /* = NULL_TREE */, return fold_to_constant (t); if (manifestly_const_eval != mce_unknown) + /* TODO: Extend the cache to be mce_value aware. And if we have a + previously cached mce_unknown result that's TREE_CONSTANT, it means + the reduced value is independent of mce_value and so we should + be able to reuse it in the mce_true/false case. */ return cxx_eval_outermost_constant_expr (t, true, true, manifestly_const_eval, false, decl); @@ -9536,7 +9567,7 @@ maybe_constant_value (tree t, tree decl /* = NULL_TREE */, || (TREE_CONSTANT (t) && !TREE_CONSTANT (r)) || !cp_tree_equal (r, t)); if (!c.evaluation_restricted_p ()) - cv_cache->put (t, r); + cv_cache->put (orig_t, r); return r; } @@ -11024,6 +11055,9 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now, case CO_AWAIT_EXPR: case CO_YIELD_EXPR: case CO_RETURN_EXPR: + if (flags & tf_error) + constexpr_error (cp_expr_loc_or_loc (t, input_location), fundef_p, + "%qE is not a constant expression", t); return false; /* Assume a TU-local entity is not constant, we'll error later when |