[PATCH]: Rewrite tree level PRE

[Eric Botcazou]

> This triggers a latent issue in SCCVN (it breaks bootstrap on x86_64 with
> Ada).
>
> copy_reference_ops_from_ref for ARRAY_REF also needs to record
> TREE_OPERAND (ref, 2) (likewise foro COMPONENT_REF).

Yes, we just ran into the problem with our 4.3-based compiler (but the 
testcase doesn't fail with the FSF 4.3 compiler).  We need something like


2008-07-11  Eric Botcazou  <ebotcazou@adacore.com>

	* tree-ssa-pre.c (create_component_ref_by_pieces) <COMPONENT_REF>:
	Deal with operand #2 as well.
	* tree-ssa-sccvn.c (copy_reference_ops_from_ref) <COMPONENT_REF>:
	Likewise.
	<ARRAY_REF>: Likewise.


to overcome the problem.  Should I install it on the 4.3 branch after testing?

-- 
Eric Botcazou
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