[LLVMdev] PR4174

[Jakub Staszak]

On Aug 21, 2009, at 10:27 PM, Eli Friedman wrote:

> On Fri, Aug 21, 2009 at 5:05 PM, Jakub Staszak<kuba at gcc.gnu.org>  
> wrote:
>>
>> On Aug 21, 2009, at 10:02 PM, Eli Friedman wrote:
>>
>>> On Fri, Aug 21, 2009 at 4:53 PM, Jakub Staszak<kuba at gcc.gnu.org>  
>>> wrote:
>>>>
>>>> On Aug 21, 2009, at 8:46 PM, Eli Friedman wrote:
>>>>
>>>>> On Fri, Aug 21, 2009 at 3:29 PM, Jakub Staszak<kuba at gcc.gnu.org>  
>>>>> wrote:
>>>>>>
>>>>>> On Aug 21, 2009, at 7:31 PM, Eli Friedman wrote:
>>>>>>
>>>>>>> On Fri, Aug 21, 2009 at 2:06 PM, Jakub Staszak<kuba at gcc.gnu.org>
>>>>>>> wrote:
>>>>>>>>
>>>>>>>> Hello,
>>>>>>>>
>>>>>>>> This patch fixes PR4174. Two test-cases included: original  
>>>>>>>> one from
>>>>>>>> bugzilla
>>>>>>>> and a little bit complicated made be myself.
>>>>>>>
>>>>>>> I think you want isSafeToSpeculativelyExecute rather than
>>>>>>> mayHaveSideEffects.  Otherwise, looks fine.
>>>>>>
>>>>>> With isSafeToSpeculativelyExecute "make check" fails on some  
>>>>>> tests,
>>>>>> i.e:
>>>>>> test/Transforms/LoopIndexSplit/SaveLastValue-2007-08-17.ll
>>>>>> because of PHI (isSafeToSpeculativelyExecute == false).
>>>>>
>>>>> isSafeToSpeculativelyExecute returns false for PHI nodes because  
>>>>> it
>>>>> isn't really clear what to do in that case... here, it's safe, so
>>>>> isSafeToSpeculativelyExecute || isa<PHINode> is probably best.
>>>>
>>>> Another two "hacks" are needed: for BranchInst and for  
>>>> IntrinsicInst.
>>>>
>>>> Patch attached.
>>>
>>> IntrinsicInst isn't necessarily safe...
>>
>>
>> Without IntrinsicInst we break
>> test/Transforms/LoopIndexSplit/SplitValue-2007-08-24-dbg.ll.
>
> Checking for isa<DbgInfoIntrinsic> is safe.

Ah, right :) Thanks for your help. I hope that everything is OK now.

New patch attached.

-Jakub
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