re PR tree-optimization/33291 (a+=2; a+=2 not simplified to a+=4; with -O3 ...

re PR tree-optimization/33291 (a+=2; a+=2  not simplified to  a+=4;  with -O3   (ok with gcc-4.2.1))

2007-09-04  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/33291
	* tree-pretty-print.c (dump_generic_node): Dump all
	qualifiers for pointer types, not only first.  Dump
	qualifiers for aggregate types as well.
	* tree-ssa-ccp.c (maybe_fold_offset_to_array_ref): Always
	use the canonical type for building ARRAY_REFs.
	* gimplify.c (canonicalize_addr_expr): Clean up.  The
	correct validness check is compatibility of the pointer
	types.  Always use the canonical type for building
	ARRAY_REFs and ADDR_EXPRs.
	* tree-ssa-forwprop.c (forward_propagate_addr_expr): Revert
	change that disabled propagation of ADDR_EXPRs into statements
	with volatile ops.

	* gcc.dg/volatile2.c: New testcase.
	* gcc.dg/pr32721.c: Adjust volatile reference pattern.
	* gcc.dg/tree-ssa/forwprop-1.c: Remove xfail.
	* gcc.dg/tree-ssa/forwprop-2.c: Likewise.
	* gcc.dg/tree-ssa/pr17141-1.c: Likewise.

From-SVN: r128068