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<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>Hi,<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'>I have a question regarding StrongPHIElimination.<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 (weak) PHIElimination, register classes seems to take
care of themselves, but with the Strong version, I get illegal virtual register
for 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'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>In this testcase, I define the PHI operands into a bigger
(super) RC, than what the using MI can handle. Weak PHI elim handled this by
copying the PHI <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>operands into the right RC. The Strong version omitted this,
and thus produced illegal code. The PHI def-operand has the right (sub) RC at
entrance of PHIElim.<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 lang=SV style='font-size:10.0pt;
font-family:Arial'>%vreg1:SuperRC<def><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=SV style='font-size:10.0pt;
font-family:Arial'>%vreg3<RC> = PHI %vreg1, %vreg2<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=SV style='font-size:10.0pt;
font-family:Arial'>Mul %vreg3, …<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=SV style='font-size:10.0pt;
font-family:Arial'>%vreg2:SuperRC<def><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span lang=SV 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'>This type of code will let the mul instruction use a virtreg
with the SuperRC, with the StrongPHIElimination.<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'>I wonder what are the purposes of the weak respective strong
phi-eliminations? Do you think I might end up with fewer COPY’s in the
end if I manually inserted <o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
font-family:Arial'>the needed COPY’s to the narrow RC’s in preRA
and then run the StrongPHIElimination?<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'>Jonas<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>
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