re PR debug/80025 (ICE w/ -O2 (-O3, -Ofast) -g -ftracer (infinite recursion in rtx_equal_for_cselib_1))

	PR debug/80025
	* cselib.h (rtx_equal_for_cselib_1): Add depth argument.
	(rtx_equal_for_cselib_p): Pass 0 to it.
	* cselib.c (cselib_hasher::equal): Likewise.
	(rtx_equal_for_cselib_1): Add depth argument.  If depth
	is 128, don't look up VALUE locs and punt.  Increment
	depth in recursive calls when walking VALUE locs.

	* gcc.dg/torture/pr80025.c: New test.

From-SVN: r246606