PR c/39613
	* c-typeck.c (do_case): If case label is not an INTEGER_CST, fold
	it and pedwarn if this results in an INTEGER_CST.

testsuite:
	* gcc.dg/case-const-1.c, gcc.dg/case-const-2.c,
	gcc.dg/case-const-3.c: New tests.

From-SVN: r145793