<html><head><meta http-equiv="Content-Type" content="text/html charset=windows-1252"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><br><div><div>On Dec 18, 2012, at 3:39 PM, Chandler Carruth <<a href="mailto:chandlerc@google.com">chandlerc@google.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div style="font-family: arial, helvetica, sans-serif; font-size: 10pt"><div dir="ltr"><div class="gmail_default" style="">On Tue, Dec 18, 2012 at 3:36 PM, Tim Northover <span dir="ltr"><<a href="mailto:t.p.northover@gmail.com" target="_blank" class="cremed">t.p.northover@gmail.com</a>></span> wrote:<br>
</div><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">> > Maybe it's naive, but I would expect it to be easy for each backend to<br>
> > expose a constant N which is the length of the longest mnemonic, and then<br>
> > for the printer to pad to N+1 or N+2….<br>
><br>
> That would probably work for X86, but other targets (ARM in particular)<br>
> often have operands which are printed/parsed as suffices on the mnemonic<br>
> itself. Because of these, the backend does not statically know the longest<br>
> potential string-of-stuff-before-the-tab.<br>
<br>
</div>Are you thinking of something beyond the ".F32.I16" suffixes (for<br>
example)? If not, the result may not be TableGeneratable, but is<br>
probably conservatively known as "8 + natural mnemonic length" for<br>
these purposes.<br></blockquote><div><br></div><div style="">The great thing is, if its close enough, it doesn't matter if there exist corner cases that are formatted less well.</div></div></div></div></div>
</blockquote></div><br><div>It affects pretty much all ARM instructions, which can have a predicate suffix. Some can also have an S suffix. Those are not expressed to tblgen as part of the mnemonic, so it can't know about them when computing a maximum mnemonic length.</div><div><br></div><div>--Owen</div></body></html>