re PR debug/36728 ([stack]: gdb doesn't work with stack alignment)

re PR debug/36728 ([stack]: gdb doesn't work with stack alignment)

	PR debug/36728
	PR debug/55467
	PR middle-end/55507
	PR bootstrap/55511
	* cselib.c (cselib_process_insn): If cselib_preserve_constants,
	don't reset table and exit early on volatile insns and setjmp.
	Reset table afterwards on setjmp.

	* gcc.dg/guality/pr36728-1.c: Include "../nop.h", make sure the asm
	are non-empty and add dependency between the first and second asm.
	* gcc.dg/guality/pr36728-2.c: Likewise.
	* gcc.dg/guality/pr36728-3.c: New test.
	* gcc.dg/guality/pr36728-4.c: New test.

From-SVN: r193911