re PR tree-optimization/60770 (disappearing clobbers)

re PR tree-optimization/60770 (disappearing clobbers)

2014-11-03  Marc Glisse  <marc.glisse@inria.fr>

	PR tree-optimization/60770
gcc/
	* tree-into-ssa.c (rewrite_update_stmt): Return whether the
	statement should be removed.
	(maybe_register_def): Likewise. Replace clobbers with default
	definitions.
	(rewrite_dom_walker::before_dom_children): Remove statement if
	rewrite_update_stmt says so.
	* tree-ssa-live.c: Include tree-ssa.h.
	(set_var_live_on_entry): Do not mark undefined variables as live.
	(verify_live_on_entry): Do not check undefined variables.
	* tree-ssa.h (ssa_undefined_value_p): New parameter for the case
	of partially undefined variables.
	* tree-ssa.c (ssa_undefined_value_p): Likewise.
	(execute_update_addresses_taken): Do not drop clobbers.

gcc/testsuite/
	* gcc.dg/tree-ssa/pr60770-1.c: New file.

From-SVN: r217034