[llvm-commits] [llvm] r48491 - in /llvm/trunk: lib/CodeGen/SelectionDAG/DAGCombiner.cpp test/CodeGen/X86/field-extract-use-trunc.ll

[Christopher Lamb]

The isTruncateFree code would also report 'true' for an i27 -> i14  
truncate the way it's currently written, BTW.

On Mar 19, 2008, at 9:56 AM, Christopher Lamb wrote:

> DAGCombine runs both before and after legalize, so I don't think  
> you can assume that MVT::i1 will be promoted. As I said elsewhere,  
> checking if the sext operation is legal for the type didn't fix the  
> problem.
>
> On Mar 19, 2008, at 2:11 AM, Duncan Sands wrote:
>
>> Hi Evan,
>>
>>> Well... Actually it should return true. MVT::i1 is promoted to  
>>> MVT::i8
>>> so on x86 it really should be free.
>>
>> some operations involving i1 are considered legal on x86, for example
>> an extending load from i1.  Maybe this has something to do with it.
>>
>> Ciao,
>>
>> Duncan.
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
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>
> --
> Christopher Lamb
>
>
>

--
Christopher Lamb



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