This is the failure of the new assertion added in the REG_ARGS_SIZE case of 
distribute_notes in the combiner on a degenerated case (complete folding of a 
dynamic stack allocation).  Fixed by dropping the note if the resulting insn 
is a no-op move.

Tested on i586-suse-linux, applied on the mainline.


2011-10-16  Eric Botcazou  <ebotcazou@adacore.com>

	PR rtl-optimization/50615
	* combine.c (distribute_notes) <REG_ARGS_SIZE>: Skip if I3 is a no-op.


2011-10-16  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc.dg/vla-23.c: New test.


-- 
Eric Botcazou