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Re: [PATCH] Allow tree-ssa Forward Prop to produce VIEW_CONVERT_EXPR in some cases


On Sun, May 4, 2008 at 9:40 PM, Andrew Pinski <pinskia@gmail.com> wrote:
> On Fri, May 2, 2008 at 4:12 AM, Andrew Pinski <pinskia@gmail.com> wrote:
>> ?Hmm, yes to both the above. ?Guess I have to look more into this than
>> ?just that. ?I will add both of these testcases.
>
> So there was a change between 4.1.1 and the trunk I did not notice
> until now which caused volatile checks needed to be added. ?Before in
> 4.1.1, we used to not look at volatile use statements but now on the
> trunk we do.
>
>> ?> ?Also if you cannot use fold_build1 because of the invalid gimple issue,
>> ?> ?won't you run into this problem with fold_stmt as well?
>>
>> ?For some reason fold_stmt does not change it, I think it tries but
>> ?rejects it as invalid gimple.
>
> Here is the new patch which fixes all three problems; we also fold the
> VCE now and regimplify the statement when needed.
>
> OK? Bootstrapped and tested on i686-linux-gnu with no regressions.
>
> Thanks,
> Andrew Pinski
>
> * tree-ssa-forwprop.c (forward_propagate_addr_expr_1): If we have the
> same size types for the indirect reference on the rhs, then create a VCE.
>
> * gcc.dg/tree-ssa/forwprop-5.c: New testcase.
> * gcc.dg/tree-ssa/forwprop-6.c: New testcase.
> * gcc.dg/tree-ssa/forwprop-7.c: New testcase.
> * gcc.dg/tree-ssa/forwprop-8.c: New testcase.
> * gcc.dg/tree-ssa/forwprop-9.c: New testcase.
>

This caused:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44900#c15

-- 
H.J.


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