[patch] Get rid of useless EH cleanups at -O0

[Eric Botcazou]

Hi,

this patchlet makes it possible to get rid of useless EH cleanups generated at 
-O0 in Ada for simple constructs involving VLAs:

  declare
    S : String (1 .. N);
  begin
    ...
  end;

by duplicating finally blocks that contain only a stack restore.  Then the EH 
optimization machinery (which is also run at -O0) can remove the cleanups.

Tested on x86_64-suse-linux, OK for the mainline?


2015-09-14  Eric Botcazou  <ebotcazou@adacore.com>

	* tree-eh.c (lower_try_finally_dup_block): Clear location information
	on stack restore statements.
	(decide_copy_try_finally): Do not consider a stack restore statement as
	coming from sources.


2015-09-14  Eric Botcazou  <ebotcazou@adacore.com>

	* gnat.dg/array24.adb: New test.

-- 
Eric Botcazou
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