c: fix crash when checking for compatibility of structures [PR116726]releases/gcc-14

When checking for compatibility of structure or union types in
tagged_types_tu_compatible_p, restore the old value of the pointer to
the top of the temporary cache after recursively calling comptypes_internal
when looping over the members of a structure of union.  While the next
iteration of the loop overwrites the pointer, I missed the fact that it can
be accessed again when types of function arguments are compared as part
of recursive type checking and the function is entered again.

	PR c/116726

gcc/c/ChangeLog:

	* c-typeck.cc (tagged_types_tu_compatible_p): Restore value
	of the cache after recursing into comptypes_internal.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr116726.c: New test.

(cherry picked from commit 9227a64495d5594613604573b72422e8e3722fc5)

0 files changed, 0 insertions, 0 deletions