commit 6b19e40f982829c460439d270d34c5c848d90c6e
author Jason Merrill <jason@redhat.com> Wed Jul 02 18:03:57 2025 -0400
committer Jason Merrill <jason@redhat.com> Thu Jul 03 10:43:37 2025 -0400
tree b919d26483faae482c1dbfbbf50d227cba2f52b0
parent c612c500de3804b330090fe478b5e055944ff8b2

c++: uninitialized TARGET_EXPR and constexpr [PR120684]

In r15-7532 for PR118856 I introduced a TARGET_EXPR with a
TARGET_EXPR_INITIAL of void_node to express that no initialization is done.
And indeed evaluating that doesn't store a value for the TARGET_EXPR_SLOT
variable.

But then at the end of the full-expression, destroy_value stores void_node
to express that its lifetime has ended.  If we evaluate the same
full-expression again, global_ctx->values still holds the void_node, causing
confusion when we try to destroy it again.  So clear out any value before
evaluating a TARGET_EXPR_INITIAL of void_type.

	PR c++/120684
	PR c++/118856

gcc/cp/ChangeLog:

	* constexpr.cc (cxx_eval_constant_expression) [TARGET_EXPR]: Clear
	the value first if is_complex.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp23/range-for10.C: New test.