<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On 27 November 2013 08:43, Evgeniy Stepanov <span dir="ltr"><<a href="mailto:eugeni.stepanov@gmail.com" target="_blank">eugeni.stepanov@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Also note that tail merging of calls happens in CodeGen, not in SimplifyCFG.<br>
</blockquote><div></div></div><br></div><div class="gmail_extra">Hi Evgenly,</div><div class="gmail_extra"><br></div><div class="gmail_extra">What we need is the general information that we want to avoid too much code motion, from choosing the passes, to choosing steps on the passes, to lowering code differently.<br>
</div><div class="gmail_extra"><br></div><div class="gmail_extra">On the front-end layer, It's as simple as dealing -O levels.</div><div class="gmail_extra"><br></div><div class="gmail_extra">On the middle-end, we could have front-ends to set a flag "debug-illusion" on each individual pass, so that they could use this information to take decisions locally, independent of the -O level (which they don't have access to). This flag should only be set if the user requests -g and the optimization level is not greater than 1.</div>
<div class="gmail_extra"><br></div><div class="gmail_extra">On the back-end, I think the only place global enough that the front-end has access to is the Target description, which could have a similar flag to avoid folding too much during codegen.</div>
<div class="gmail_extra"><br></div><div class="gmail_extra">cheers,</div><div class="gmail_extra">--renato</div></div>