re PR c++/86524 (std::less with pointer arguments not usable in static_assert in constexpr function)
PR c++/86524
PR c++/88446
* cp-tree.h (cp_fold_maybe_rvalue, cp_fold_rvalue): Declare.
(fold_non_dependent_expr): Add manifestly_const_eval argument.
* constexpr.c (cxx_eval_builtin_function_call): Evaluate
__builtin_constant_p if ctx->manifestly_const_eval even in constexpr
functions. Don't reuse dummy{1,2} vars between different arguments.
Use cp_fold_rvalue instead of cp_fully_fold. Fix comment typo.
(fold_non_dependent_expr): Add manifestly_const_eval argument, pass
it through to cxx_eval_outermost_constant_expr and
maybe_constant_value.
* cp-gimplify.c (cp_fold_maybe_rvalue, cp_fold_rvalue): No longer
static.
* semantics.c (finish_static_assert): Call fold_non_dependent_expr
with true as manifestly_const_eval.
* g++.dg/cpp1y/constexpr-86524.C: New test.
* g++.dg/cpp2a/is-constant-evaluated4.C: New test.
* g++.dg/cpp2a/is-constant-evaluated5.C: New test.
* g++.dg/cpp2a/is-constant-evaluated6.C: New test.
From-SVN: r267341
