r178687 - in /trunk/gcc: ChangeLog testsuite/Ch...

[rguenth at gcc dot gnu dot org]

Author: rguenth
Date: Thu Sep  8 13:00:23 2011
New Revision: 178687

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=178687
Log:
2011-09-08  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/19831
	* tree-ssa-dce.c (mark_all_reaching_defs_necessary_1): Also
	skip builtins with vdefs that do not really store something.
	(propagate_necessity): For calls to free that we can associate
	with an allocation function do not mark the freed pointer
	definition necessary.
	(eliminate_unnecessary_stmts): Remove a call to free if
	the associated call to an allocation function is not necessary.

	* gcc.dg/tree-ssa/pr19831-1.c: New testcase.
	* gcc.dg/tree-ssa/pr19831-2.c: Likewise.
	* gcc.dg/tree-ssa/pr19831-3.c: Likewise.
	* gcc.dg/errno-1.c: Adjust.

Added:
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr19831-1.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr19831-2.c
    trunk/gcc/testsuite/gcc.dg/tree-ssa/pr19831-3.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/errno-1.c
    trunk/gcc/tree-ssa-dce.c