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<div class="moz-cite-prefix">On 07/05/2017 09:58 AM, Anastasiya
Ruzhanskaya wrote:<br>
</div>
<blockquote
cite="mid:CAH7gUZbKV-vTdGRF=VCo5=K4-SL5TZWHTwp=eC9GALocYL85iA@mail.gmail.com"
type="cite">
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<div>Oh, yes...strange<br>
<code><span style="color:rgb(0,0,0)">attributes </span><span
style="color:rgb(136,0,0)">#0 = { noinline nounwind
optnone uwtable "correctly-rounded-divide-<wbr>sqrt-fp-math"="false"
"disable-tail-calls"="false" "less-precise-fpmad"="false"
"no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-<wbr>leaf"
"no-infs-fp-math"="false" "no-jump-tables"="false"
"no-nans-fp-math"="false" "no-signed-zeros-fp-math"="<wbr>false"
"no-trapping-math"="false" "stack-protector-buffer-size"=<wbr>"8"
"target-cpu"="x86-64" "target-features"="+fxsr,+mmx,<wbr>+sse,+sse2,+x87"
"unsafe-fp-math"="false" "use-soft-float"="false" }</span><span
style="color:rgb(0,0,0)"></span><span
style="color:rgb(0,0,0)"><br>
<br>
</span></code></div>
<code><span style="color:rgb(0,0,0)">How this can be avoided? it
is always so after clang -s -emit-llvm<br>
</span></code></div>
</blockquote>
<br>
This is because clang defaults to -O0, and in that mode, does not
produce IR that is intended to be optimized. You probably want to
do:<br>
<br>
clang -S -emit-llvm -O3 -mllvm -disable-llvm-optzns<br>
<br>
to get out the unoptimized IR.<br>
<br>
-Hal<br>
<br>
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cite="mid:CAH7gUZbKV-vTdGRF=VCo5=K4-SL5TZWHTwp=eC9GALocYL85iA@mail.gmail.com"
type="cite">
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<div class="gmail_extra"><br>
<div class="gmail_quote">2017-07-05 16:49 GMT+02:00 Hal Finkel <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:hfinkel@anl.gov" target="_blank">hfinkel@anl.gov</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
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<div class="m_-773001609585264129moz-cite-prefix">On
07/04/2017 04:25 AM, Anastasiya Ruzhanskaya via
llvm-dev wrote:<br>
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<div>Hello,<br>
</div>
I am developing now a compiler, based
on llvm infrastructure, so I am building
my own sequence of llvm passes with some
adjustable options. <br>
<br>
</div>
I can't find really clear info about some
cases, so maybe you can help, and write:<br>
<br>
</div>
<div>0) Why I should always delete
attributes before applying optimizations
with opt command? With attributes
specified no optimization can be applied.<br>
</div>
</div>
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</div>
</blockquote>
<br>
</span> You definitely shouldn't delete attributes in
general. Does your attribute set include optnone?<br>
<br>
-Hal<br>
<br>
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<div>
<div>
<div><br>
</div>
Where I can get real benefit from:<br>
</div>
1) Constant Hoisting<br>
</div>
<div>-only when we have some large reusable
constants in program?<br>
</div>
2) argpomotion<br>
</div>
- this option does not always replace all my args
by reerence with values, when I specify it.<br>
</div>
</div>
<br>
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<pre>______________________________<wbr>_________________
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</font></span></blockquote><span class="HOEnZb"><font color="#888888">
<pre class="m_-773001609585264129moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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</blockquote></div>
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</blockquote>
<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre></body></html>