[llvm-commits] [llvm] r47569 - /llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp

[Dan Gohman]

On Feb 25, 2008, at 2:38 PM, Chris Lattner wrote:

>
> On Feb 25, 2008, at 2:15 PM, Dan Gohman wrote:
>
>> Author: djg
>> Date: Mon Feb 25 16:15:55 2008
>> New Revision: 47569
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=47569&view=rev
>> Log:
>> Add an assert to verify that we don't see an
>> {S,U}MUL_LOHI with an unused high value.
>
> Hey Dan,
>
> Is this a correctness or a performance thing?  If we chose to turn of
> the dag combiner at -O0, could this assertion get triggered?
>

It's a performance thing. I guess it's theoretically possible for a dead
umulh to go through codegen at -O0, in which case this would trip.
I'll take it out.

Dan