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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I am attempting to lower the selectCC instruction to the
instruction set of the backend I’m working on and I cannot seem to find a
way to correctly implement this instruction. I know how this instruction should
get implemented; I just have yet to find a way to do it. I want the select_cc
instruction to be lowered into a comparison followed by a conditional move. I’ve
attempted to use a custom rule pasted below, but it keeps giving me an error
about the first argument. <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>What I attempted is as follows:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>class InstFormat<dag outs, dag ins, string asmstr,
list<dag> pattern> <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> : Instruction {<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> let Namespace = "Inst";<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> dag OutOperandList = outs;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> dag InOperandList = ins;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> let Pattern = pattern;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> let AsmString = asmstr;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>}<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>def SDTGenTernaryOp : SDTypeProfile<1, 3, [
SDTCisSameAs<0, 1>,SDTCisSameAs<0, 2>, SDTCisSameAs<0, 3>
]>;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>def cmov_logical : SDNode<"INSTISD::CMOVLOG",
SDTGenTernaryOp>;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>let PrintMethod = "printCCOperand" in<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> def CCOp : Operand<i32>;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>def CMOVLOG : InstFormat<(outs
GPR:$dst), (ins GPR:$LHS, GPR:$RHS, GPR:$TVAL, GPR:$FVAL, CCOp:$cond),<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>
"$cond $LHS, $LHS, $RHS\ncmov_logical $dst, $LHS, $TVAL, $FVAL",<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>
[(set GPR:$dst, (selectcc GPR:$LHS, GPR:$RHS, GPR:$TVAL, GPR:$FVAL, CCOp:$cond))]>;<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Maybe I’m approaching this from the wrong way, but I
don’t think this transformation should be that difficult.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Basically I want dst = select $LHS, $RHS, $TVAL, $FVAL,
$condOp to be transformed into<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>$condOp tmp, $LHS, $RHS<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>cmov_logical dst, tmp, $TVAL, $FVAL<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>My attempt at doing so with a custom OperationAction also
failed. So, what would I need to do to figure out how to implement this
correctly? Is there any place you can point me to which shows how to go from a
single instruction to multiple consecutive instructions? A function that I can
study would be nice since my problem is even though I can look at the other
backends, I don’t completely understand everything that is going on so I
probably overlooked this already.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Thanks,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Micah Villmow<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Systems Engineer<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Advanced Technology & Performance<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Advanced Micro Devices Inc.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns0:Street w:insAuthor="Micah Villmow"
w:insDate="2008-09-11T18:05:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-09-11T18:05:00Z"><ns0:address w:insAuthor="Micah Villmow"
w:insDate="2008-09-11T18:05:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-09-11T18:05:00Z"><st1:Street w:st="on"><st1:address w:st="on">4555
Great America Pkwy</st1:address></st1:Street></ns0:address></ns0:Street>,<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'><ns0:place w:insAuthor="Micah Villmow"
w:insDate="2008-09-11T18:05:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-09-11T18:05:00Z"><ns0:City w:insAuthor="Micah Villmow"
w:insDate="2008-09-11T18:05:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-09-11T18:05:00Z"><st1:City w:st="on"><st1:place w:st="on">Santa
Clara</st1:place></st1:City></ns0:City></ns0:place>, CA. 95054<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>P: 408-572-6219<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>F: 408-572-6596</span></font><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
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