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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>I have a simple program that generates correct intermediate
representation. However, when working on my backend, and my lowering function
gets called. The comparison operation is flipped via an invalid transformation.
i.e. gt </span></font><font size=2 face=Wingdings><span style='font-size:10.0pt;
font-family:Wingdings'>è</span></font><font size=2 face=Arial><span
style='font-size:10.0pt;font-family:Arial'> le, lt </span></font><font size=2
face=Wingdings><span style='font-size:10.0pt;font-family:Wingdings'>è</span></font><font
size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> ge etc..<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>define void @test_fc_if_gt(double %x, double %y, double
addrspace(11)* %result) {<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>entry:<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %x.addr = alloca
double ; <double*>
[#uses=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'> %y.addr = alloca
double ; <double*>
[#uses=2]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %result.addr =
alloca double
addrspace(11)*
; <double addrspace(11)**> [#uses=2]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> store double %x,
double* %x.addr<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> store double %y,
double* %y.addr<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> store double
addrspace(11)* %result, double addrspace(11)** %result.addr<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %tmp = load double*
%x.addr
; <double> [#uses=1]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %tmp1 = load
double*
%y.addr ;
<double> [#uses=1]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> <b><span
style='font-weight:bold'>%cmp = fcmp ogt double %tmp,
%tmp1
; <i1> [#uses=1]<o:p></o:p></span></b></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> br i1 %cmp, label
%ifthen, label %ifend<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'>ifthen: ; preds
= %entry<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %tmp2 = load
double addrspace(11)**
%result.addr
; <double addrspace(11)*> [#uses=1]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> %tmp3 = load
double*
%x.addr ;
<double> [#uses=1]<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> store double
%tmp3, double addrspace(11)* %tmp2<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> br label %ifend<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'>ifend:
; preds = %ifthen, %entry<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'> ret void<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'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>With the above kernel run through llc with -march=x86 -view-dag-combine1-dags
I still see the ogt as the comparison operation, but when I run it with llc
-march=x86 -view-legalize-dags the ogt node has been transformed into a ule.<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'>So, my question is, how do I get llvm to stop doing invalid translation
of comparison instructions? This problem affects my custom backend and I have
reproduced it with the x86 backend.<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="2008-11-10T14:56:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-11-10T14:56:00Z"><ns0:address w:insAuthor="Micah Villmow"
w:insDate="2008-11-10T14:56:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-11-10T14:56:00Z"><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="2008-11-10T14:56:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-11-10T14:56:00Z"><ns0:City w:insAuthor="Micah Villmow"
w:insDate="2008-11-10T14:56:00Z" w:endInsAuthor="Micah Villmow"
w:endInsDate="2008-11-10T14:56:00Z"><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>
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12.0pt'><o:p> </o:p></span></font></p>
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