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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">Thanks! That’s probably close enough for practical purposes. I looked at the overrides on various targets, and they all return true if the FMA hardware exists.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D">- Arch<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Jingyue Wu [mailto:jingyue@google.com]
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<b>Sent:</b> Wednesday, December 10, 2014 2:56 PM<br>
<b>To:</b> Robison, Arch<br>
<b>Cc:</b> llvmdev@cs.uiuc.edu<br>
<b>Subject:</b> Re: [LLVMdev] Best way for JIT to query whether llvm.fma.* is fast?<o:p></o:p></span></p>
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<p class="MsoNormal">Does TargetLowering::isFMAFasterThanFMulAndFAdd (<a href="http://llvm.org/docs/doxygen/html/TargetLowering_8h_source.html#l01499">http://llvm.org/docs/doxygen/html/TargetLowering_8h_source.html#l01499</a>) help? <o:p></o:p></p>
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<p class="MsoNormal">Jingyue<o:p></o:p></p>
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<p class="MsoNormal">On Wed, Dec 10, 2014 at 12:48 PM, Robison, Arch <<a href="mailto:arch.robison@intel.com" target="_blank">arch.robison@intel.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">For the Julia language JIT, we’d like be able to tell whether the llvm.fma.* intrinsic has hardware support. What’s the best way to query LLVM (JIT) for this information?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">The information would be used in situations where the user wants to use different algorithms depending on whether FMA hardware is present or not.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">- Arch D. Robison
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_______________________________________________<br>
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<a href="http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev" target="_blank">http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev</a><o:p></o:p></p>
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