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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'>So this change did indeed have an effect! </span><span style='font-size:11.0pt;font-family:Wingdings;color:#1F497D'>J</span><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><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>I’m seeing regressions in a number of benchmarks mainly due to a host of extra bitcasts that get introduced. Here’s the problem I’m seeing in a nutshell:<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'>1) There is a Phi with input type double<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>2) Polly demotes the phi into a load/store of type double<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>3) InstCombine canonicalizes the load/store to use i64 instead of double<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>4) SROA removes the load/store & inserts a phi back in, using i64 as the type. Inserts bitcast to get to double.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D'>5) The bitcast sticks around and eventually get translated into FMOVs (for AArch64 at least).<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 function findCommonType() in SROA.cpp is used to obtain the type that should be used for the new alloca that SROA wants to create. It’s decision process is essentially – if all loads/stores of alloca are the same, use that type; else use the corresponding integer type. This causes bitcasts to be inserted in a number of places, most all of which stick around. <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'>I’ve copied a reduced version of an instance of the problem below. I’m looking for comments on what others think is the right solution here. Make SROA more intelligent about picking the type? <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 code is below with all unnecessary code removed for easy consumption. <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'>Daniel<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><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>Before </span></u><u><span style='font-size:11.0pt;font-family:"Courier New";color:#212121'>Polly – Prepare code for polly</span></u><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> we have code that looks like:</span></u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.cond473: ; preds = %while.cond473.outer78, %while.body475<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%p_j_x452.0</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= phi double [ </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%105</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>, %while.body475 ], [ %p_j_x452.0.ph82, %while.cond473.outer78 ]<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.body475: ; preds = %while.cond473<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %sub480 = fsub fast double %64, </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%p_j_x452.0</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%105</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= load double* %x485, align 8, !tbaa !25<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>After </span></u><u><span style='font-size:11.0pt;font-family:"Courier New";color:#212121'>Polly – Prepare code for polly</span></u><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> we have:</span></u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.cond473: ; preds = %while.cond473.outer78, %while.body475<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%p_j_x452.0.reload</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= load double* %p_j_x452.0.reg2mem<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.body475: ; preds = %while.cond473<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %sub480 = fsub fast double %64, </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%p_j_x452.0.reload</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%110</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= load double* %x485, align 8, !tbaa !25<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> store double </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%110</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>, double* %p_j_x452.0.reg2mem<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>After </span></u><u><span style='font-size:11.0pt;font-family:"Courier New";color:#212121'>Combine redundant instructions</span></u><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> :</span></u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.cond473: ; preds = %while.cond473.outer78, %while.body475<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%p_j_x452.0.reload</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= load double* %p_j_x452.0.reg2mem, align 8<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.body475: ; preds = %while.cond473<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %sub480 = fsub fast double %74, </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%p_j_x452.0.reload</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %x485 = getelementptr inbounds %struct.CompAtom* %15, i64 %idxprom482, i32 0, i32 0<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %194 = bitcast double* %x485 to i64*<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%195</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= load i64* %194, align 8, !tbaa !25<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %200 = bitcast double* %p_j_x452.0.reg2mem to i64*<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> store i64 </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%195</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>, i64* %200, align 8<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>After </span></u><u><span style='font-size:11.0pt;font-family:"Courier New";color:#212121'>SROA</span></u><u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> :</span></u><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.cond473: ; preds = %while.cond473.outer78, %while.body475<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %p_j_x452.0.reg2mem.sroa.0.0.p_j_x452.0.reload362 = phi i64 [ %p_j_x452.0.ph73.reg2mem.sroa.0.0.load368, %while.cond473.outer78 ], [ </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%178</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>, %while.body475 ]<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%173</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= bitcast i64 %p_j_x452.0.reg2mem.sroa.0.0.p_j_x452.0.reload362 to double<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>while.body475: ; preds = %while.cond473<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %sub480 = fsub fast double %78, </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#0070C0'>%173</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %x485 = getelementptr inbounds %struct.CompAtom* %15, i64 %idxprom482, i32 0, i32 0<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> %177 = bitcast double* %x485 to i64*<o:p></o:p></span></p><div style='mso-element:para-border-div;border:none;border-bottom:solid windowtext 1.0pt;padding:0in 0in 1.0pt 0in'><p class=MsoNormal style='border:none;padding:0in'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'> </span><b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'>%178</span></b><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:red'> </span><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'>= load i64* %177, align 8, !tbaa !25<o:p></o:p></span></p><p class=MsoNormal style='border:none;padding:0in'><span style='font-size:11.0pt;font-family:"Calibri",sans-serif;color:#212121'><o:p> </o:p></span></p></div><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><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'> llvmdev-bounces@cs.uiuc.edu [mailto:llvmdev-bounces@cs.uiuc.edu] <b>On Behalf Of </b>Chandler Carruth<br><b>Sent:</b> Wednesday, January 21, 2015 8:32 PM<br><b>To:</b> Pete Cooper<br><b>Cc:</b> LLVM Developers Mailing List<br><b>Subject:</b> Re: [LLVMdev] RFC: Missing canonicalization in LLVM<o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>On Wed, Jan 21, 2015 at 3:06 PM, Pete Cooper <<a href="mailto:peter_cooper@apple.com" target="_blank">peter_cooper@apple.com</a>> wrote:<o:p></o:p></p><blockquote style='border:none;border-left:solid #CCCCCC 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt'><p class=MsoNormal>Sounds good to me. Integers it is then.<o:p></o:p></p></blockquote></div><p class=MsoNormal><br>FYI, thanks, I'm just going to commit this then. It seems we're all in essential agreement. We can revert it and take a more cautious approach if something terrible happens. =]<o:p></o:p></p></div></div></div></body></html>