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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Bastien,<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'>Weird gcc is generating fma for my platform STEricsson Novathor with Linaro, code works. It also works when I use LLVM to generate fma (using llc –mtriple=armv7-eabi). Maybe someone from ARM can answer the question ?<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'>Seb<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:0in 0in 0in 4.0pt'><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> JF Bastien [mailto:jfb@google.com] <br><b>Sent:</b> Friday, November 09, 2012 5:36 PM<br><b>To:</b> Sebastien DELDON-GNB<br><b>Cc:</b> Anitha Boyapati; llvmdev@cs.uiuc.edu<br><b>Subject:</b> Re: [LLVMdev] fmac generation for cortex-a9<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>AFAIK A9 doesn't have VFPv4 or AdvSIMDv2, so it doesn't have VFMA. I don't know what LLVM does, but it shouldn't emit VFMA when you target A9. VMLA isn't a fused multiply-add, it's a multiply followed by an add and has different latency as well as precision.<o:p></o:p></span></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><o:p> </o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>On Thu, Nov 8, 2012 at 4:57 AM, Sebastien DELDON-GNB <<a href="mailto:sebastien.deldon@st.com" target="_blank">sebastien.deldon@st.com</a>> wrote:<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Hi Anitha,<br><br>Thanks for your answer but -mcpu=cortex-a9 -mattr=+vfp4 doesn' t enable fused mac generation for me.<br>I would like just to understand why -mtriple=armv7-eabi enables it while -mcpu=cortex-a9 seems to disable it ?<br><br>Seb<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><br>> -----Original Message-----<br>> From: Anitha Boyapati [mailto:<a href="mailto:anitha.boyapati@gmail.com">anitha.boyapati@gmail.com</a>]<br>> Sent: Thursday, November 08, 2012 10:22 AM<br>> To: Sebastien DELDON-GNB<br>> Cc: <a href="mailto:llvmdev@cs.uiuc.edu">llvmdev@cs.uiuc.edu</a><br>> Subject: Re: [LLVMdev] fmac generation for cortex-a9<br>><br>> On 8 November 2012 13:56, Sebastien DELDON-GNB<br>> <<a href="mailto:sebastien.deldon@st.com">sebastien.deldon@st.com</a>> wrote:<br>> > Hi all,<br>> ><br>> ><br>> ><br>> ><br>> ><br>> > I've a .ll code that use double precision fmul/fadd or fmul/fsub. When<o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>> > I compile it using llc -mcpu=cortex-a9 I couldn't get vmla/vmls<br>> > generated even using -fp-contract=fast, but when I use option<br>> > -mtriple=armv7-eabi instead of -mcpu=cortex-a9 fused mac are<o:p></o:p></span></p><div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>> generated. Can someone explain me why ?<br>> ><br>><br>> Perhaps you need to use some attributes. -mattr=+vfp4 Check fusedMAC.ll<br>> from ARM codegen tests.<br>><br>><br>> --<br>> Anitha<br><br>_______________________________________________<br>LLVM Developers mailing list<br><a href="mailto:LLVMdev@cs.uiuc.edu">LLVMdev@cs.uiuc.edu</a> <a href="http://llvm.cs.uiuc.edu" target="_blank">http://llvm.cs.uiuc.edu</a><br><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></span></p></div></div></div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'><o:p> </o:p></span></p></div></div></div></div></body></html>