https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115639
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
With
static_assert(0==big_calc()); // (1)
we evaluate the big_calc call twice. Once, while parsing the static_assert:
#0 cxx_eval_call_expression (ctx=0x7fffffffc3e0, t=<call_expr 0x7fffea3c5b40>,
lval=vc_prvalue,
non_constant_p=0x7fffffffc50f, overflow_p=0x7fffffffc50e) at
/home/mpolacek/src/gcc/gcc/cp/constexpr.cc:2801
#1 0x0000000000e45583 in cxx_eval_constant_expression (ctx=0x7fffffffc3e0,
t=<call_expr 0x7fffea3c5b40>,
lval=vc_prvalue, non_constant_p=0x7fffffffc50f, overflow_p=0x7fffffffc50e,
jump_target=0x0)
at /home/mpolacek/src/gcc/gcc/cp/constexpr.cc:7554
#2 0x0000000000e4b6b8 in cxx_eval_outermost_constant_expr (t=<call_expr
0x7fffea3c5b40>, allow_non_constant=true,
strict=true, manifestly_const_eval=mce_value::mce_unknown,
constexpr_dtor=false, object=<tree 0x0>)
at /home/mpolacek/src/gcc/gcc/cp/constexpr.cc:8852
#3 0x0000000000e4c8ee in maybe_constant_value (t=<call_expr 0x7fffea3c5b40>,
decl=<tree 0x0>,
manifestly_const_eval=mce_value::mce_unknown) at
/home/mpolacek/src/gcc/gcc/cp/constexpr.cc:9161
#4 0x0000000000e95c58 in cp_fully_fold (x=<call_expr 0x7fffea3c5b40>,
manifestly_const_eval=mce_value::mce_unknown)
at /home/mpolacek/src/gcc/gcc/cp/cp-gimplify.cc:2852
#5 0x0000000000e95dc7 in cp_fully_fold (x=<call_expr 0x7fffea3c5b40>)
at /home/mpolacek/src/gcc/gcc/cp/cp-gimplify.cc:2871
#6 0x000000000122ee78 in cp_build_binary_op (location=..., code=EQ_EXPR,
orig_op0=<non_lvalue_expr 0x7fffea3cd540>,
orig_op1=<call_expr 0x7fffea3c5b40>, complain=3) at
/home/mpolacek/src/gcc/gcc/cp/typeck.cc:6669
#7 0x0000000000dc774e in build_new_op (loc=..., code=EQ_EXPR, flags=1,
arg1=<non_lvalue_expr 0x7fffea3cd540>,
arg2=<call_expr 0x7fffea3c5b40>, arg3=<tree 0x0>, lookups=<tree 0x0>,
overload=0x7fffffffcc30, complain=3)
at /home/mpolacek/src/gcc/gcc/cp/call.cc:7516
and the second time while in finish_static_assert:
#0 cxx_eval_call_expression (ctx=0x7fffffffce20, t=<call_expr 0x7fffea3c5b40>,
lval=vc_prvalue,
non_constant_p=0x7fffffffcf4f, overflow_p=0x7fffffffcf4e) at
/home/mpolacek/src/gcc/gcc/cp/constexpr.cc:2801
#1 0x0000000000e45583 in cxx_eval_constant_expression (ctx=0x7fffffffce20,
t=<call_expr 0x7fffea3c5b40>,
lval=vc_prvalue, non_constant_p=0x7fffffffcf4f, overflow_p=0x7fffffffcf4e,
jump_target=0x0)
at /home/mpolacek/src/gcc/gcc/cp/constexpr.cc:7554
#2 0x0000000000e35b6b in cxx_eval_binary_expression (ctx=0x7fffffffce20,
t=<eq_expr 0x7fffea3cc5a0>, lval=vc_prvalue,
non_constant_p=0x7fffffffcf4f, overflow_p=0x7fffffffcf4e) at
/home/mpolacek/src/gcc/gcc/cp/constexpr.cc:3820
#3 0x0000000000e46f1f in cxx_eval_constant_expression (ctx=0x7fffffffce20,
t=<eq_expr 0x7fffea3cc5a0>, lval=vc_prvalue,
non_constant_p=0x7fffffffcf4f, overflow_p=0x7fffffffcf4e, jump_target=0x0)
at /home/mpolacek/src/gcc/gcc/cp/constexpr.cc:7966
#4 0x0000000000e4b6b8 in cxx_eval_outermost_constant_expr (t=<eq_expr
0x7fffea3cc5a0>, allow_non_constant=true,
strict=true, manifestly_const_eval=mce_value::mce_true,
constexpr_dtor=false, object=<tree 0x0>)
at /home/mpolacek/src/gcc/gcc/cp/constexpr.cc:8852
#5 0x0000000000e4c7c2 in maybe_constant_value (t=<eq_expr 0x7fffea3cc5a0>,
decl=<tree 0x0>,
manifestly_const_eval=mce_value::mce_true) at
/home/mpolacek/src/gcc/gcc/cp/constexpr.cc:9140
#6 0x0000000000e4ce02 in fold_non_dependent_expr (t=<eq_expr 0x7fffea3cc5a0>,
complain=3, manifestly_const_eval=true,
object=<tree 0x0>) at /home/mpolacek/src/gcc/gcc/cp/constexpr.cc:9280
#7 0x00000000011dd851 in finish_static_assert (condition=<eq_expr
0x7fffea3cc5a0>, message=<string_cst 0x7fffcde811f8>,
location=2147483661, member_p=false, show_expr_p=false) at
/home/mpolacek/src/gcc/gcc/cp/semantics.cc:11887
The second time around, we're not finding the call in constexpr_call_table.
