commit aa1e19d821a39d973c4c8c0e8d1d19811d2fa433
author Patrick Palka <ppalka@redhat.com> Thu Jan 09 10:50:08 2025 -0500
committer Patrick Palka <ppalka@redhat.com> Thu Jan 09 17:55:11 2025 -0500
tree 6643a4a2976539a1ab344b69cdf8579f5c058273
parent 4dbfc2ff0a84edf6addeaa425272a5beacbbc7db

c++: relax ICE for unexpected trees during constexpr [PR117925]

When we encounter an unexpected (likely templated) tree code during
constexpr evaluation we currently ICE even in release mode.  But it
seems more user-friendly to just gracefully treat the expression as
non-constant, which will be harmless most of the time (e.g. in the case
of warning-specific or speculative constexpr folding as in the PR), and
at worst will transform an ICE-on-valid bug into a rejects-valid bug.
This is also what e.g. tsubst_expr does when it encounters an unexpected
tree code.

	PR c++/117925

gcc/cp/ChangeLog:

	* constexpr.cc (cxx_eval_constant_expression) <default>:
	Relax ICE when encountering an unexpected tree code into a
	checking ICE guarded by flag_checking.

Reviewed-by: Jason Merrill <jason@redhat.com>
(cherry picked from commit eeedc54cc81c4dfb472ecbd6f14cfbf2dd035474)