[llvm-commits] [PATCH] Fix PR13220

[Michael Liao]

Sorry, the root casue of PR13220 is that, during result expansion on
EXTRACT_VECTOR_ELT, the current logic assumes the input vector element
type is the same as the return type. It breaks the fact you just pointed
out. Here is the latest patch fixing the the result expansion of
EXTRACT_VECTOR_ELT.

Yours
- Michael

On Thu, 2012-07-12 at 09:52 +0200, Duncan Sands wrote:
> Hi Michael,
> 
> > Yeah, you're right. But, if the promoted type is not legal, i.e.
> > extended type. The result extending assumes the bit-width of the
> > extracted data is the same as the element of the input vector.
> 
> I was unable to parse these sentences.  Can you please say it again
> differently.
> 
> Thanks, Duncan.
> 
>   Here is
> > the latest patch distinguishing whether the promoted data result is
> > legal or not. When the promoted data type is extended one, just
> > any-extend the input vector first and then extract element; otherwise,
> > just follow the previous behavior.
> >
> > Yours
> > - Michael
> >
> > On Thu, 2012-07-12 at 09:18 +0200, Duncan Sands wrote:
> >> Hi Michael,
> >>> Please review the attached patch fixing PR13220. With this patch, the
> >>> test case in PR13220 is passed as well as 'make check-all'. Test cases
> >>> are included in this patch.
> >>
> >> it is legal for EXTRACT_VECTOR_ELT to return a wider type than the input
> >> vector element type.  Here's the doc from ISDOpcodes.h:
> >>
> >>       /// EXTRACT_VECTOR_ELT(VECTOR, IDX) - Returns a single element from VECTOR
> >>       /// identified by the (potentially variable) element number IDX.  If the
> >>       /// return type is an integer type larger than the element type of the
> >>       /// vector, the result is extended to the width of the return type.
> >>       EXTRACT_VECTOR_ELT,
> >>
> >> So if this is causing crashes then the bug is probably somewhere else, in some
> >> code that isn't expecting this.
> >>
> >> Ciao, Duncan.
> >> _______________________________________________
> >> llvm-commits mailing list
> >> llvm-commits at cs.uiuc.edu
> >> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> >
> 
> 

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