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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Hi all,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Intel has just revealed its AVX2 instruction set, to be supported by the 2013 Haswell architecture, and it's looking quite revolutionary: <a href="http://software.intel.com/en-us/forums/showthread.php?t=83399&o=a&s=lr">http://software.intel.com/en-us/forums/showthread.php?t=83399&o=a&s=lr</a><o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> It includes powerful 'gather' instructions, which allow reading multiple vector elements from non-contiguous memory locations. It also extends all integer vector instructions to 256-bit, and can shift vector elements by independent counts. This offers tremendous opportunity for auto-vectorizing loops, since practically every scalar operation will have a direct vector equivalent. It also facilitates implementing throughput computing languages like OpenCL.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>So I was wondering whether in LLVM a gather operation is best represented with a 'load' instruction taking vector operands, or whether it's better to define it as a separate 'gather' instruction. What would be the pros and cons of each approach, and what do you think should be the long-term goals for the LLVM instruction set?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Cheers,<o:p></o:p></p><p class=MsoNormal>Nicolas<o:p></o:p></p></div></body></html>