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Hi Michael,</div>
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Thanks for your reply!</div>
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Since I want to collect the counts of unique array access to array elements in one iteration, so I consider a[i] and a[i - 1] as two accesses to different array elements. Would it be possible to get the notion of "i - 1" at IR level. </div>
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The IR looks like:</div>
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<span>%11 = load float*, float** %a.addr, align 8, !dbg !954</span></div>
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%12 = load i32, i32* %i, align 4, !dbg !955
<div>%sub = sub nsw i32 %12, 1, !dbg !956<br>
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<div>%idxprom7 = sext i32 %sub to i64, !dbg !954<br>
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<span>%arrayidx8 = getelementptr inbounds float, float* %11, i64 %idxprom7, !dbg !954</span><br>
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Working the the source level might be easier, but I wonder if it is possible to know idxprom7 -> i - 1 with IR</div>
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Thanks again!</div>
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Michael</div>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Michael Kruse <llvmdev@meinersbur.de><br>
<b>Sent:</b> Tuesday, February 18, 2020 9:26 AM<br>
<b>To:</b> Michael Meng <overrainbow2013@hotmail.com><br>
<b>Cc:</b> via llvm-dev <llvm-dev@lists.llvm.org><br>
<b>Subject:</b> Re: [llvm-dev] Differentiate array access at IR level</font>
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<div class="PlainText">Note that a[i] are a[i-1] are accessing the same memory addresses,<br>
just not in the same loop iteration. You may want to look into<br>
DependenceInfo.<br>
<br>
Michael<br>
<br>
Am Mo., 17. Feb. 2020 um 00:04 Uhr schrieb Michael Meng via llvm-dev<br>
<llvm-dev@lists.llvm.org>:<br>
><br>
> Hi LLVM community,<br>
><br>
> I am trying to differentiate access to different array elements, for example:<br>
><br>
> for (int i = 1; i < 10; i++) {<br>
><br>
> a[i] = a[i] + 10;<br>
><br>
> b[i] = a[i - 1] * 2;<br>
><br>
> }<br>
><br>
> If it is possible to tell it loads/stores 3 different array elements: a[i], b[i] and a[i - 1] at IR level?<br>
><br>
><br>
> Thanks for your time in advance!<br>
><br>
><br>
> Best,<br>
> Michael<br>
> _______________________________________________<br>
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