<div dir="auto">I do not think we have this framework of conditionally kicking in analysis passes. But one can always do "intelligent" prior setting of attribute over function which can be checked in getAnalysisUsage for a perticular pass to conditionally enable needed analysis.<div dir="auto"><br></div><div dir="auto">Cheers</div><div dir="auto"><div dir="auto">Jatin </div><div dir="auto"><div dir="auto"><br><div class="gmail_quote"><div dir="ltr">On Tue, 24 Apr 2018, 04:33 Friedman, Eli via llvm-dev, <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
<div class="m_2643682578738763853moz-cite-prefix">I probably wouldn't worry about the
cost of LoopInfo; it's relatively cheap to compute. But if you're
really concerned, you can run your pass after a pass which
preserves LoopInfo (so it's free because it was already
computed). Or you can stick your code into an existing pass which
requires LoopInfo anyway, like LoopIdiomRecognize.<br>
<br>
-Eli<br>
<br>
On 4/23/2018 3:37 PM, Anom LLVM wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Thanks for the answer Eli.
<div><br>
</div>
<div>I think I was a little too vague in my question. The
program has the following structure:</div>
<div>void foo() {</div>
<div> bar();<br>
}</div>
<div><br>
</div>
<div>void bar() {</div>
<div> for (..) {</div>
<div> __builtin_compute()</div>
<div> }</div>
<div>}</div>
<div><br>
</div>
<div>We would like to use scalar evolution + loopinfowrapperpass
inside instcombine only if __builtin_compute is present.
instcombine can convert the loop into a single builtin ie.</div>
<div><br>
</div>
<div>void bar() {</div>
<div> __builtin_wide_compute();</div>
<div>}</div>
<div><br>
</div>
<div>When the inliner runs on foo(), we want bar() to already
have the transformation to reflect the cost of the inlining
decision more accurately. </div>
<div><br>
</div>
<div>I do see that scalar evolution is a lazy but
loopwrapinfopass is not. Is there a way to run these two
analysis passes conditionally before inlining?</div>
<div><br>
</div>
<div>Thanks,</div>
<div><br>
</div>
<div>Stan</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Apr 20, 2018 at 1:55 PM,
Friedman, Eli <span dir="ltr"><<a href="mailto:efriedma@codeaurora.org" target="_blank" rel="noreferrer">efriedma@codeaurora.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span>On 4/19/2018 1:57 PM, Anom LLVM via llvm-dev
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Hi,<br>
<br>
I have pass phase ordering question.<br>
<br>
I am interested in performing a transformation that
matches several LLVM IR instructions and converts them
to a single builtin. This sort of transformation must
occur prior to inlining because inlining needs to
analyze cost of the builtin. However, the LLVM IR ->
builtin transformation requires scalar evolution which
typically doesn't run until after the inliner.<br>
</blockquote>
<br>
</span>
This isn't right, or at least, not the complete picture;
loop optimization passes run interleaved with the inliner.
(Try looking at the output of "-debug-pass=Executions" to
see exactly what's happening.)<span><br>
<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
My question is, is there a way to run scalar evolution
conditionally prior to inlining? I'd like to leave
compile time unaffected if my code doesn't contain any
of these builtins.<br>
</blockquote>
<br>
</span>
ScalarEvolution is lazy, so it's essentially free if you
don't query it.<span class="m_2643682578738763853HOEnZb"><font color="#888888"><br>
<br>
-Eli<br>
<br>
-- <br>
Employee of Qualcomm Innovation Center, Inc.<br>
Qualcomm Innovation Center, Inc. is a member of Code
Aurora Forum, a Linux Foundation Collaborative Project<br>
<br>
</font></span></blockquote>
</div>
<br>
</div>
</blockquote>
<p><br>
</p>
<pre class="m_2643682578738763853moz-signature" cols="72">--
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project</pre>
</div>
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