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Re: RFA: Don't destroy SCEV cache in copy-prop
On Tue, Dec 7, 2010 at 5:34 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Sat, Dec 4, 2010 at 9:10 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Fri, Nov 26, 2010 at 7:03 AM, Michael Matz <matz@suse.de> wrote:
>>> Hello,
>>>
>>> while working on something else I got a segfault in SCEV analysis because
>>> it contained stale SSA names. ?The reason is that copy-prop always DCEs
>>> the propagated copies, invalidating SCEV entries referring to the LHS of
>>> those. ?We could either reset the SCEV cache (at the expense of having to
>>> recompute it again), or simply not do DCE when we have loops. ?I chose the
>>> latter.
>>>
>>> I've also removed the superflous copy-prop in the graphite pipeline, it's
>>> no use to run two copy-props next to each other.
>>>
>>> Unfortunately I don't have a testcase that fails with an unmodified GCC.
>>>
>>> Regstrapping on x86_64-linux (all langs + Ada) in progress. ?Okay if that
>>> passes?
>>>
>>>
>>
>> This caused:
>>
>> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46799
>>
>
> This also caused:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46834
>
This also caused:
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46994
--
H.J.