re PR rtl-optimization/87761 ([MIPS] New FAIL: gcc.target/mips/fix-r4000-10.c ...

re PR rtl-optimization/87761 ([MIPS] New FAIL: gcc.target/mips/fix-r4000-10.c   -O1 start with r265398)

	PR rtl-optimization/87761
	* regcprop.c (copyprop_hardreg_forward_1): Check may_trap_p on SET,
	not INSN.  Also check RTX_FRAME_RELATED_P.  Queue insns for DF rescan
	as needed.
	(pass_cprop_hardreg::execute): Add df note problem and defer insn
	rescans.  Reprocess blocks as needed, calling df_analyze before
	reprocessing.  Always call df_analyze before fixing up debug bind
	insns.

From-SVN: r269896