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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I agree with Micah and Guy that the sampler type should be an opaque type. The i32 solution has too many cons, and the pros are not clear-cut either. (For example, I don’t quite understand why constant propagation on samplers should even work.)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>The problem with renaming of opaque types should better be solved by extending LLVM to disallow renaming given types.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Without seeing a follow-up patch, I cannot comment on the use of functions to initialize samplers. In our implementation, we use both opaque types and metadata, which works fine.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Anton.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Villmow, Micah [mailto:Micah.Villmow@amd.com] <br><b>Sent:</b> 12 October 2012 00:02<br><b>To:</b> Tanya Lattner<br><b>Cc:</b> Benyei, Guy; cfe-dev@cs.uiuc.edu; Anton Lokhmotov<br><b>Subject:</b> RE: [cfe-dev] OpenCL & SPIR specific types - proposal and patch<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div style='border:none;border-left:solid blue 1.5pt;padding:0cm 0cm 0cm 4.0pt'><div><div><p class=MsoNormal><span lang=EN-US>If the type gets renamed, how are you going to identify what is a sampler?<o:p></o:p></span></p><p class=MsoNormal><b><i><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>[Villmow, Micah] Usage.</span></i></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>See my comment above about linking and opaque types as it doesn't solve that problem for you either.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>Can you please share your list of pros and cons of pointer to opaque type versus int? <o:p></o:p></span></p><p class=MsoNormal><b><i><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>[Villmow, Micah] Sure, here is what I view as the pros and cons.<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Opaque type:<o:p></o:p></span></i></b></p><p class=MsoNormal><b><i><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Pros:<o:p></o:p></span></i></b></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Implementation details are target dependent<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>No confusion with valid i32 type<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Utilizes the type system instead of metadata<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Can be materialized to i32 if needed<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>No operations can occur on the type.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Easier to track through stack.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Cons:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Can be renamed and loose information<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Requires initialization function<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Requires global variables<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>I32:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Pros:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Can be initialized inline and constant propagated.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Already works(for AMD at least).<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Metadata can make for easy identification if it exists.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Maps 1-1 to initializers<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Cons:<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Optimizers don’t know the differences between sampler and other i32<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Harder to track through stack<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>An integer i32 and a sampler_t i32 is only determined by usage and not type.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Operations can work on the type, which is illegal.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Metadata can be lost requiring extensive analysis which cannot always be determined.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US>-Tanya<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div></div></div></div></div></body></html>