re PR tree-optimization/27799 (adding unused char field inhibits optimization)

2008-04-23  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/27799
	PR tree-optimization/32921
	PR tree-optimization/32624
	* tree-ssa-structalias.c (merge_smts_into): Only merge the
	SMTs aliases and the tag itself into the solution.
	* tree-ssa-alias.c (compute_flow_sensitive_aliasing): Do not
	merge the points-to solution back into the SMT aliases.
	(may_alias_p): Use alias_set_subset_of instead of
	aliases_conflict_p.  A pointer which points to
	memory with alias set zero may access any variable.

	* gcc.dg/tree-ssa/pr27799.c: New testcase.
	* gcc.dg/tree-ssa/20030807-7.c: Remove xfail, scan vrp dump.

From-SVN: r134598