re PR middle-end/71581 (ICE on valid code on x86_64-linux-gnu with -Wuninitialized (Segmentation fault))

	PR middle-end/71581
	* tree-ssa-uninit.c (warn_uninit): If EXPR and VAR are NULL,
	see if T isn't anonymous SSA_NAME with COMPLEX_EXPR created
	for conversion of scalar user var to complex type and use the
	underlying SSA_NAME_VAR in that case.  If EXPR is still NULL,
	punt.

	* gcc.dg/pr71581.c: New test.

From-SVN: r237621