re PR target/39139 (ICE with stringop and register var)

re PR target/39139 (ICE with stringop and register var)

	PR target/39139
	* function.h (struct function): Add has_local_explicit_reg_vars
	bit.
	* gimplify.c (gimplify_bind_expr): Set it if local DECL_HARD_REGISTER
	VAR_DECLs were seen.
	* tree-ssa-live.c (remove_unused_locals): Recompute
	cfun->has_local_explicit_reg_vars.
	* tree-ssa-sink.c (statement_sink_location): Don't sink BLKmode
	copies or clearings if cfun->has_local_explicit_reg_vars.

	* gcc.target/i386/pr39139.c: New test.

From-SVN: r144065