<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 28, 2015, at 3:47 PM, Hal Finkel <<a href="mailto:hfinkel@anl.gov" class="">hfinkel@anl.gov</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">----- Original Message -----</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">From: "Matt Arsenault" <<a href="mailto:Matthew.Arsenault@amd.com" class="">Matthew.Arsenault@amd.com</a>><br class="">To: "<a href="mailto:llvmdev@cs.uiuc.edu" class="">llvmdev@cs.uiuc.edu</a>" <<a href="mailto:LLVMdev@cs.uiuc.edu" class="">LLVMdev@cs.uiuc.edu</a>><br class="">Sent: Wednesday, January 28, 2015 1:52:59 PM<br class="">Subject: [LLVMdev] RFC: Add ISD nodes for mad<br class=""><br class="">Hi,<br class=""><br class="">I would like to add an ISD node for an fmad operation (named either<br class="">FMAD<br class="">or FMULADD). It will have the semantics of returning the same result<br class="">as<br class="">the separate multiply and add with the intermediate rounding step,<br class="">and<br class="">not a differently rounded result. The motivation is to share code<br class="">with<br class="">the various FMA forming DAG combines, but will be generally more<br class="">useful<br class="">on targets that support it since it is OK to form without non-default<br class="">-fp-contract modes.<br class=""></blockquote><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">Why not just reuse the existing FMA node, but add an additional parameter to indicate whether enhanced intermediate precision is required?</span></div></blockquote></div><br class=""><div class="">Because that would break a lot of existing backends?</div><div class=""><br class=""></div><div class="">—Owen</div></body></html>