<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=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Nov 2, 2018, at 5:44 AM, Dangeti Tharun kumar <<a href="mailto:cs15mtech11002@iith.ac.in" class="">cs15mtech11002@iith.ac.in</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><br class=""><br class=""><div class="gmail_quote"><div dir="ltr" class="">On Fri, Nov 2, 2018 at 3:31 PM Anton Korobeynikov <<a href="mailto:anton@korobeynikov.info" target="_blank" class="">anton@korobeynikov.info</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">> Yes, I am compiling for linux system.<br class="">
> So the RA will not consider assigning a scratch register to a live range crossing function call, though it may reduce spills?<br class="">
Well, it has to spill the register – otherwise it could be clobbered by a call. </blockquote><div class="">May be, I haven't conveyed it properly. What I mean was, does the RA make an analysis of spills incurred by <i class="">using a scratch register and spilled/restored across the call site</i> and <i class="">by not using the scratch register at all </i>?</div></div></div></div></blockquote><div><br class=""></div><div>As far as I read the calling conventions for linux/mac there isn't a single callee saved XMM register, so there is not XMM register for which this would work:</div><div><br class=""></div><div>%XMMx = ...</div><div>callq ... # <= this may change the value of XMMx</div><div>use %XMMx</div></div></body></html>