llvm dev - Sep 2008 - [LLVMdev] Cannot Select ConstantFP on x86

I just ran into this today with x86-64:

Cannot yet select: 0x3cbc180: f64 = ConstantFP <1>

As far as I can tell, DAGCombiner comes along and sees an sint_to_fp of the 
constant 1 and hapilly folds it into a ConstantFP<1>.  ISel then blows up 
because there's no pattern for it.

Does this look familiar to anyone?  I don't see any relevant bugs in the 
database.

                                           -Dave

On Sep 24, 2008, at 5:11 PM, David Greene wrote:
> I just ran into this today with x86-64:
>
> Cannot yet select: 0x3cbc180: f64 = ConstantFP <1>
>
> As far as I can tell, DAGCombiner comes along and sees an sint_to_fp  
> of the
> constant 1 and hapilly folds it into a ConstantFP<1>.  ISel then  
> blows up
> because there's no pattern for it.
Sounds like a bug if dag combiner is doing this after legalization.  
DAG combiner should never form anything that's illegal after  
legalization has completed.

Evan
>
>
> Does this look familiar to anyone?  I don't see any relevant bugs in  
> the
> database.
>
>                                           -Dave
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On Sep 24, 2008, at 5:11 PM, David Greene wrote:
> I just ran into this today with x86-64:
>
> Cannot yet select: 0x3cbc180: f64 = ConstantFP <1>
>
> As far as I can tell, DAGCombiner comes along and sees an sint_to_fp  
> of the
> constant 1 and hapilly folds it into a ConstantFP<1>.  ISel then  
> blows up
> because there's no pattern for it.
>
> Does this look familiar to anyone?  I don't see any relevant bugs in  
> the
> database.
Do you have a testcase?  It sounds like something that would be easy  
to fix.

-Chris

On Thursday 25 September 2008 19:12, Chris Lattner
wrote:
> On Sep 24, 2008, at 5:11 PM, David Greene wrote:
> > I just ran into this today with x86-64:
> >
> > Cannot yet select: 0x3cbc180: f64 = ConstantFP <1>
> >
> > As far as I can tell, DAGCombiner comes along and sees an sint_to_fp
> > of the
> > constant 1 and hapilly folds it into a ConstantFP<1>.  ISel then
> > blows up
> > because there's no pattern for it.
> >
> > Does this look familiar to anyone?  I don't see any relevant bugs
in
> > the
> > database.
>
> Do you have a testcase?  It sounds like something that would be easy
> to fix.
I have a fix (yes, it was trivial).  I'll have to see about a testcase as
it's
proprietary code.

                                                   -Dave