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<p class="MsoNormal">Hi,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I’ve instruction scheduling problem that I cannot further investigate by myself… Could someone give me some clues?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">After Instruction selection, here is part of the generated instruction.<o:p></o:p></p>
<p class="MsoNormal"> NOP<o:p></o:p></p>
<p class="MsoNormal"> <span style="background:lime;mso-highlight:lime">MOV_AB_ro @s1, %fab_roff0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="background:lime;mso-highlight:lime"> %6:fpuaoffsetclass = COPY %fab_roff0; FPUaOffsetClass:%6</span><o:p></o:p></p>
<p class="MsoNormal"> MOV_A_oo %6, def %5; FPUaOffsetClass:%6,%5<o:p></o:p></p>
<p class="MsoNormal"> MOVSUTO_A_iSLo 24575, def %7; FPUaOffsetClass:%7<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">The order of instruction is very important: the COPY shall take place after the MOV_AB_ro!<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">But during Instruction scheduling, these two instructions have been permutated!<o:p></o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
</span>SU(18): NOP<o:p></o:p></p>
<p class="MsoNormal"><span style="background:yellow;mso-highlight:yellow">SU(20): %6:fpuaoffsetclass = COPY %fab_roff0; FPUaOffsetClass:%6</span><o:p></o:p></p>
<p class="MsoNormal">SU(<span style="background:yellow;mso-highlight:yellow">19</span>): MOV_AB_ro @s1, %fab_roff0<o:p></o:p></p>
<p class="MsoNormal">SU(21): MOV_A_oo %6, def %5; FPUaOffsetClass:%6,%5<o:p></o:p></p>
<p class="MsoNormal">SU(22): MOVSUTO_A_iSLo 24575, def %7; FPUaOffsetClass:%7<span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
<br>
<o:p></o:p></span></p>
<p class="MsoNormal">I’m trying to understand why the Instruction scheduler has swapped these two instructions…<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">From the trace, it seems that the Successors of SU(19) is SU(21) and not SU(20) as expected…<o:p></o:p></p>
<p class="MsoNormal">What kind of information between the <span style="background:lime;mso-highlight:lime">
MOV_AB_ro</span> and <span style="background:lime;mso-highlight:lime">COPY</span> could be missing?<o:p></o:p></p>
<p class="MsoNormal">How to define that the pred of SU(20) should be SU(19)?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">SU(19): MOV_AB_ro @s1, %fab_roff0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> # preds left : 1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> # succs left : 1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> # rdefs left : 0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Latency : 0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Depth : 21<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Height : 25<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Predecessors:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> SU(18): Ord Latency=1 Barrier<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> <span style="background:yellow;mso-highlight:yellow">
Successors:<o:p></o:p></span></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New";background:yellow;mso-highlight:yellow"> SU(21): Ord Latency=0 Barrier</span><span style="font-family:"Courier New""><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Pressure Diff :<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Single Issue : false;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">SU(20): %6:fpuaoffsetclass = COPY %fab_roff0; FPUaOffsetClass:%6<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> <span style="background:yellow;mso-highlight:yellow">
# preds left : 0</span><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> # succs left : 1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> # rdefs left : 0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Latency : 0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Depth : 0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Height : 25<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Successors:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New"">SU(21): Data Latency=0 Reg=%6<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Pressure Diff : FPUaOffsetClass -1 FPUabOffsetClass -1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:"Courier New""> Single Issue : false;<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><br>
<br>
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><img width="536" height="49" id="_x0000_i1025" src="http://www.spacebel.be/wp-content/uploads/2018/02/image-sign-sbp30y-1.jpg" alt="http://www.spacebel.be/wp-content/uploads/2018/02/image-sign-sbp30y-1.jpg"></span><span style="font-size:12.0pt;font-family:"Times New Roman","serif""><o:p></o:p></span></p>
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<p class="MsoNormal" align="center" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-align:center">
<b><span lang="FR-BE" style="font-size:10.0pt">Dominique Torette</span></b><span lang="FR-BE" style="font-size:10.0pt">
<br>
System Architect<br>
Rue des Chasseurs Ardennais - Liège Science Park - B-4031 Angleur <br>
Tel: +32 (0) 4 361 81 11 - Fax: +32 (0) 4 361 81 20 <br>
</span><span style="font-size:10.0pt"><a href="http://www.spacebel.be/"><span lang="FR-BE" style="color:blue">www.spacebel.be</span></a></span><span lang="FR-BE" style="font-size:12.0pt;font-family:"Times New Roman","serif""><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="FR-BE"><o:p> </o:p></span></p>
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