lra: Clobbers in a parallel are earlyclobbers (PR83245)

lra: Clobbers in a parallel are earlyclobbers (PR83245)

The documentation (rtl.texi) says:

  When a @code{clobber} expression for a register appears inside a
  @code{parallel} with other side effects, the register allocator
  guarantees that the register is unoccupied both before and after that
  insn if it is a hard register clobber.

and at least the rs6000 backend relies on that (see PR83245).  This
patch restores that behaviour.

Registers that are also used as operands in the instruction are not
treated as earlyclobber, so such insns also still work (PR80818, an
s390 testcase).

	PR rtl-optimization/83245
	* lra.c (collect_non_operand_hard_regs): Treat clobbers of non-operand
	hard registers as earlyclobber, also if not in an asm.

From-SVN: r255377