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<p class="MsoNormal"><font size="2" face="Arial"><span lang="SV" 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 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">I have a problem with the assert in Tablegen:<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="Calibri"><span style="font-size:11.0pt;
font-family:Calibri">llvm-tblgen: /dev/shm/uabpath/dev-master/utils/TableGen/RegisterInfoEmitter.cpp:204: void <anonymous namespace>::RegisterInfoEmitter::EmitRegUnitPressure(llvm::raw_ostream
&, const llvm::CodeGenRegBank &, const std::string &): Assertion `RU.Weight < 256 && "RegUnit too heavy"' failed.<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Calibri"><span style="font-size:11.0pt;
font-family:Calibri"><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 reason for this is that I have constructed pred-operands to be of the register class type FlagRegs, which holds a big union of classes, so that I can generate
code like<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">Cmp %1:RC1, 0<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">Brr #bb, if EQ:%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"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">Cmp %2:RC2, 0<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">Brr #bb, if EQ:%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"><o:p> </o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">, where RC1 and RC2 (and others as well not shown here) both share common sub-registers, but are of different widths. This construct makes it easy to predicate
instructions, no matter what register is used and of which width, and so on. (The architecture has several flag registers tied to various registers).
<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">The problem is that extremely huge values for reg unit weights result in tablegen. I suspect a circular propagation of weights, due to these common sub/super
reg-classes. <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">static const RegClassWeight RCWeightTable[] = {<o:p></o:p></span></font></p>
<p class="MsoNormal"><font size="2" face="Arial"><span style="font-size:10.0pt;
font-family:Arial">{4294967295, 4294967288}, // FlagRegs<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">Does anyone have a suggestion of how to get around this problem? It would be a big task to rewrite the instructions to have different types of pred-operands
depending of used CCReg, etc. Could perhaps the unit weight calculation be fixed to handle more intricate cases like this? Who could I work with on this in this case?<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 Paulsson<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>
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