re PR tree-optimization/32540 (Exponential time behavior in PRE)

re PR tree-optimization/32540 (Exponential time behavior in PRE)

2007-11-05  Nick Clifton  <nickc@redhat.com>
	    Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/32540
	PR tree-optimization/33922
	* doc/invoke.texi: Document PARAM_MAX_PARTIAL_ANTIC_LENGTH.
	* tree-ssa-pre.c: Include params.h.
	(compute_partial_antic_aux): Use PARAM_MAX_PARTIAL_ANTIC_LENGTH
	to limit the maximum length of the PA set for a given block.
	* Makefile.in: Add a dependency upon params.h for tree-ssa-pre.c
	* params.def (PARAM_MAX_PARTIAL_ANTIC_LENGTH): New parameter.

	* gcc.dg/tree-ssa/pr32540-1.c: New.
	* gcc.dg/tree-ssa/pr32540-2.c: New.
	* gcc.dg/tree-ssa/pr33922.c: New.

Co-Authored-By: Sebastian Pop <sebastian.pop@amd.com>
From-SVN: r129901