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<p class="MsoNormal">Hi All,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am using llvm-3.0 release version for compiling some files. I have a cpp file on which I did a few custom passes. After that I used llc to convert the *.bc file to *.s file at –O1 optimization level. llc took ~2630 seconds to perform
this conversion. I timed llc and these are the top three passes that is taking most of the time.
<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"> ---User Time--- --System Time-- --User+System-- ---Wall Time--- --- Name ---<o:p></o:p></p>
<p class="MsoNormal"> 1816.1735 ( 77.8%) 23.3215 ( 69.7%) 1839.4950 ( 77.6%) 1839.4132 ( 77.6%) Simple Register Coalescing<o:p></o:p></p>
<p class="MsoNormal"> 493.5948 ( 21.1%) 9.1846 ( 27.4%) 502.7794 ( 21.2%) 502.7681 ( 21.2%) X86 DAG->DAG Instruction Selection<o:p></o:p></p>
<p class="MsoNormal"> 5.7244 ( 0.2%) 0.0000 ( 0.0%) 5.7244 ( 0.2%) 5.7204 ( 0.2%) Machine Instruction LICM<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I am running this in a fairly new Xeon server. Furthermore, at –O0, llc takes less than 20 seconds to complete. Is this behavior expected and is there a way to disable Simple Register Coalescing pass without switching to –O0 optimization
level to get around this problem?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks<o:p></o:p></p>
<p class="MsoNormal">Sreekumar <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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