re PR rtl-optimization/29329 (internal consistency failure)

re PR rtl-optimization/29329 (internal consistency failure)

	PR rtl-optimization/29329
	* combine.c (replaced_rhs_insn): Rename to i2mod.
	(replaced_rhs_value): Rename to i2mod_new_rhs.
	(i2mod_old_rhs): New global variable.
	(combine_instructions): Adjust for above change.  Save a copy of
	the old RHS into i2mod_old_rhs when the contents of a REG_EQUAL
	note are substituted in the second instruction.
	(distribute_notes) <REG_DEAD>: Adjust for above change.  Do not
	ditch the note if it pertains to the second eliminated register
	and this register is mentioned in i2mod_old_rhs.

	Revert:
	2006-09-12  Eric Botcazou  <ebotcazou@libertysurf.fr>

	* combine.c (distribute_notes) <REG_DEAD>: Do not consider SETs past
	the insn to which the note was originally attached.

From-SVN: r121037