re PR rtl-optimization/41812 (test 20071030-1.c fails execution on powerpc64)

re PR rtl-optimization/41812 (test 20071030-1.c fails execution on powerpc64)

2009-11-30  Paolo Bonzini  <bonzini@gnu.org>

	PR rtl-optimization/41812
	* fwprop.c (local_md, local_lr): New globals.
	(process_defs, process_uses): Remove local_md argument.  Never
	consider dead pseudos to have singleton def-use chains.
	(single_def_use_enter_block): Perform LR simulation.
	(build_single_def_use_links): Remove local_md local variable.
	Add DF_NOTE.  Allocate local_lr.
	(fwprop_done): Do not remove DF_CHAIN, we do not use it anymore.
	* df-problems.c (df_md_scratch): New.
	(df_md_alloc, df_md_free): Allocate/free it.
	(df_md_local_compute): Only include live registers in init.
	(df_md_transfer_function): Prune the in-set computed by
	the confluence function, and the gen-set too.
	(df_simulate_one_insn_forwards): Fix typo.

From-SVN: r154753