<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 11, 2019 at 1:01 AM Aaron Ballman <<a href="mailto:aaron.ballman@gmail.com">aaron.ballman@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 11, 2019, 9:51 AM Mehdi AMINI <<a href="mailto:joker.eph@gmail.com" target="_blank">joker.eph@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Jun 11, 2019 at 12:37 AM Aaron Ballman <<a href="mailto:aaron.ballman@gmail.com" rel="noreferrer" target="_blank">aaron.ballman@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto">Sorry for the brevity, I am currently travelling and responding on a cell phone. I won't be able to give you a full accounting until later,</div></blockquote><div><br></div><div>There is no hurry right now!</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"> but 1) I don't see a motivating problem this churn solves, 2) signed int does not represent the full size of an object like size_t does and is inappropriate to use for addressing into objects or arrays, which means we won't use this convention consistently anyway.</div></blockquote><div><br></div><div>As far as I can tell, the same arguments applies to "unsigned" I believe: it does not represent the full extent of size_t on every platform either! Yet we're still using it as an index, including to index into objects/array.</div></div></div></div></blockquote></div></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div class="gmail_quote"><div><br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"> I have yet to be convinced by the c++ community's very recent desire to switch everything to signed integers and would be very unhappy to see us switch without considerably more motivating rarionale.</div></blockquote><div><br></div><div>Note that this is not about "switching" anything: there is no standard in LLVM right now (as far as I know) and the codebase is inconsistent (I am using `int` in general for a while I believe).</div></div></div></div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">Glad to hear there's no plan to change the codebase</div></div></blockquote><div><br></div><div>Just like every guideline, new code should follow unless there is a good reason not to (the wording is "prefer").</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto">, but then I fail to see the purpose of the coding rule. Won't it boil down to "use the correct datatype for what you're doing?"</div></div></blockquote><div><br></div><div>How do you define what is the correct datatype?</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br></div><div dir="auto">What I mostly want to avoid is code that uses signed values for inherently unsigned operations like comparing against the size of an object.</div></div></blockquote><div><br></div><div>I believe `if (index < v.size() - 1)` can be very surprising when v.empty().</div><div><br></div><div>-- </div><div>Mehdi</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><div class="gmail_quote"><div>-- </div><div>Mehdi</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br><br><div class="gmail_quote" dir="auto"><div dir="ltr" class="gmail_attr">On Mon, Jun 10, 2019, 11:04 PM Mehdi AMINI <<a href="mailto:joker.eph@gmail.com" rel="noreferrer" target="_blank">joker.eph@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jun 10, 2019 at 10:32 AM Aaron Ballman via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="noreferrer noreferrer" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jun 10, 2019, 7:16 PM Jake Ehrlich via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="noreferrer noreferrer" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto">I'm in the same situation James is in and thus have the same bias but I'll +1 that comment nevertheless. I think I prefer using size_t or the uintX_t types where applicable. Only when I need a signed value do I use one.</div></blockquote></div></div><div dir="auto"><br></div><div dir="auto">+1 to prefering unsigned types.</div></div></blockquote><div><br></div><div>I'd appreciate if you guys could provide rational that address the extensive arguments and opinion provided in the C++ community that I tried to summarize in the link above.</div><div>Otherwise I don't know what to take out of unmotivated "+1".</div><div><br></div><div>-- </div><div>Mehdi</div><div><br></div><div><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="auto"><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jun 10, 2019, 9:59 AM James Henderson via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="noreferrer noreferrer noreferrer" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>Maybe it's just because I work in code around the binary file formats almost exclusively, but unsigned (or more often uint64_t) is FAR more common than int everywhere I go. I don't have time right now to read up on the different links you provided, and I expect this is covered in them, but it also seems odd to me to use int in a loop when indexing in a container (something that can't always be avoided), given the types of size() etc.</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 10 Jun 2019 at 17:26, Michael Kruse via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" rel="noreferrer noreferrer noreferrer noreferrer" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-style:solid;border-left-color:rgb(204,204,204);padding-left:1ex">Am Sa., 8. Juni 2019 um 13:12 Uhr schrieb Tim Northover via llvm-dev<br>
<<a href="mailto:llvm-dev@lists.llvm.org" rel="noreferrer noreferrer noreferrer noreferrer" target="_blank">llvm-dev@lists.llvm.org</a>>:<br>
> I'd prefer us to have something neater than static_cast<int> for the<br>
> loop problem before we made that change. Perhaps add an ssize (or<br>
> equivalent) method to all of our internal data structures? They're a<br>
> lot more common than std::* containers.<br>
<br>
+1<br>
<br>
Since C++20 is also introducing ssize [1] members, this makes a lot of<br>
sense to me. Using it would help avoiding an unsigned comparison as in<br>
<br>
if (IndexOfInterestingElement >= Container.size())<br>
...<br>
<br>
to sneak in from the start.<br>
<br>
Michael<br>
<br>
[1] <a href="http://wg21.link/p1227r1" rel="noreferrer noreferrer noreferrer noreferrer noreferrer" target="_blank">http://wg21.link/p1227r1</a><br>
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