[llvm-commits] [llvm] r93202 - /llvm/trunk/lib/Transforms/InstCombine/InstCombineCasts.cpp

[Chris Lattner]

On Jan 12, 2010, at 11:04 AM, Dan Gohman wrote:

>
> On Jan 11, 2010, at 2:49 PM, Chris Lattner wrote:
>
>> Author: lattner
>> Date: Mon Jan 11 16:49:40 2010
>> New Revision: 93202
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=93202&view=rev
>> Log:
>> reenable the piece that turns trunc(zext(x)) -> x even if zext has  
>> multiple uses,
>> codegen has no apparent problem with the trunc version of this,  
>> because it turns
>> into a simple subreg idiom
>
> On targets where TargetLowering::isTruncateFree returns true,
> at least.

Are you concerned about a specific target?  This xform in general only  
applies when the source and dest are both 'native' integer types.

-Chris