<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 1 Mar 2018, at 9:52 am, Chris Lattner 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=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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="">On
Feb 27, 2018, at 10:25 AM, Tom Stellard via llvm-dev <</span><a href="mailto:llvm-dev@lists.llvm.org" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">llvm-dev@lists.llvm.org</a><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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="">>
wrote:</span>
<blockquote type="cite" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;" class="">
There is no requirement that the tool needs to be an official part of the LLVM<br class="">
project to implement to use it this way For example, the cuda toolchain<br class="">
in clang relies on a few proprietary tools from NVIDIA.<br class="">
<br class="">
I think too much emphasis is being placed on having this tool be part of the<br class="">
LLVM project.<br class="">
</blockquote>
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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-caps: normal; font-weight: normal; letter-spacing: 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="">Agreed.
Why is it good for LLVM to include this tool?</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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="">
<br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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-caps: normal; font-weight: normal; letter-spacing: 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="">If
there was a strong rationale for doing so, it would probably make sense to be a new subproject of some sort rather than included in the main llvm repo (not sure if that is what was being proposed).</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: 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="">
</div>
</blockquote>
</div>
<div class=""><br class="">
</div>
While what Tom has said may be true for clang, it is not the only frontend that wants to use this. LDC currently uses a fork of LLVM to generate SPIR-V it would be much nicer to be able to use the regular LLVM releases.
<div class=""><br class="">
<div class="">The converter (the tool being proposed) is effectively both a backend (LLVM IR -> SPIR-V), albeit not a conventional one, and a frontend (SPIR-V -> LLVM IR) and therefore needs a number of things from the LLVM repo such as its own triples (and
intrinsics when we move away from the current system).</div>
<div class="">It being proposed as a tool is an intermediate step to a backend and a tool that calls some of the backends passes.</div>
<div class=""><br class="">
</div>
<div class="">The rationale is to:</div>
<div class="">Provide a standard LLVM tooling with SPIR-V that benefits frontends through the SPIR-V backend to produce SPIR-V, and backends (CPU and GPU) through the SPIR-V frontend so that intrinsics can be translated (possibly a lá libclc?) and the triple
changed and fed through the backend. </div>
<div class="">Reduce the fragmentation of the SPIR-V ecosystem, I know of at least three projects aiming to provide SPIR-V tooling for LLVM. Having one central project allows coordinated effort and ensures that the SPIR-V tooling stays up to date with LLVM.</div>
<div class=""><br class="">
</div>
<div class="">Nic</div>
</div>
</body>
</html>