<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">+gisel folks<div class=""><br class=""></div><div class="">Hi Alex,</div><div class=""><br class=""></div><div class="">You’re doing the right thing.</div><div class="">That’s a known limitation that we’ve discussed in <a href="https://reviews.llvm.org/D59227" class="">https://reviews.llvm.org/D59227</a> but we didn’t really reach a conclusion back them.</div><div class="">Short term, I believe you’re right, we should patch up the GISel emitter to use <span style="font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;" class="">getConstantVRegVal instead of looking directly for G_CONSTANT.</span></div><div class=""><font face="Helvetica Neue, Helvetica, Arial, sans-serif" class=""><br class=""></font></div><div class=""><font face="Helvetica Neue, Helvetica, Arial, sans-serif" class="">Long term, this is something we need to discuss. I personally think that we shouldn’t consider G_CONSTANT as true instructions and we should always extend them in place, but this is not a generally belief.</font></div><div class=""><font face="Helvetica Neue, Helvetica, Arial, sans-serif" class=""><br class=""></font></div><div class=""><font face="Helvetica Neue, Helvetica, Arial, sans-serif" class="">Cheers,</font></div><div class=""><font face="Helvetica Neue, Helvetica, Arial, sans-serif" class="">-Quentin<br class=""></font><div><br class=""><blockquote type="cite" class=""><div class="">On May 20, 2019, at 5:49 AM, via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" class="">llvm-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div style="font-family: 'Helvetica Neue',Helvetica,Arial,sans-serif; font-size: 12px;" class="">Hi all,<br class=""><br class=""><div class="">I'm trying to get GlobalISel up and running on an off-tree architecture and am thinking I must be doing something wrong, given by how few things actually work.</div><div class=""><br class=""></div><div class="">Namely, any ImmLeaf<> pattern will fail to match if there is a (TRUNC/ZEXT/SEXT) applied to the constant operand, all of which are commonly created through Legalization. This is due to G_CONSTANT being explicitly looked for by the tablegened code, rather than code that makes use of getConstantVRegVal.<br class=""></div><br class=""><div class="">Is there supposed to be a constant folding pass before Instruction Selection? CSE does not fold past unaries applied to operands, I'm surely missing a pass somewhere...</div><div class=""><br class="">Thanks,<br class=""></div><div class="">- Alex Davies</div></div>
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