Re: [PATCH] wwwdocs: gcc-14: Add RISC-V changes

[Kito Cheng <kito.cheng@sifive.com>]

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Committed with fixes, thanks :)

On Thu, Apr 11, 2024 at 12:18 AM Palmer Dabbelt <palmer@dabbelt.com> wrote:

> On Wed, 10 Apr 2024 00:58:00 PDT (-0700), kito.cheng@sifive.com wrote:
> > ---
> >  htdocs/gcc-14/changes.html | 155 ++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 154 insertions(+), 1 deletion(-)
> >
> > diff --git a/htdocs/gcc-14/changes.html b/htdocs/gcc-14/changes.html
> > index 2d8968cf..6cbb2e8f 100644
> > --- a/htdocs/gcc-14/changes.html
> > +++ b/htdocs/gcc-14/changes.html
> > @@ -739,7 +739,160 @@ __asm (".global __flmap_lock"  "\n\t"
> >
> >  <!-- <h3 id="s390">S/390, System z, IBM z Systems</h3> -->
> >
> > -<!-- <h3 id="riscv">RISC-V</h3> -->
> > +<h3 id="riscv">RISC-V</h3>
> > +<ul>
> > +  <li>The SLP and loop vectorizer is now enabled for RISC-V when the
> vector
>
> I think "are now enabled"?
>
> > +      extension is enabled, thanks to Ju-Zhe Zhong from
> > +      <a href='https://rivai-ic.com.cn/'>RiVAI</a>,
> > +      Pan Li from <a href='https://www.intel.com/'>Intel</a>, and
> Robin Dapp
> > +      from <a href='https://www.ventanamicro.com/'>Ventana Micro</a>
> for
> > +      contributing most of the implementation!</li>
> > +  <li>The <code>-mrvv-max-lmul=</code> option has been introduced for
> > +      performance tuning of the loop vectorizer. The default value is
> > +      <code>-mrvv-max-lmul=m1</code>, which limits the maximum LMUL to
> 1.
> > +      The <code>-mrvv-max-lmul=dynamic</code> setting can dynamically
> select
> > +      the maximum LMUL value based on register pressure.</li>
> > +  <li>Atomic code generation has been improved and is now in
> conformance with
> > +      the latest psABI specification, thanks to Patrick O'Neill from
> > +      <a href='https://www.rivosinc.com/'>Rivos</a>.</li>
> > +  <li>Support for the vector intrinsics as specified in
> > +      <a href='
> https://github.com/riscv-non-isa/rvv-intrinsic-doc/tree/v1.0.x'>
> > +      version 1.0 of the RISC-V vector intrinsic specification</a>.</li>
> > +  <li>Support for the experimental vector crypto intrinsics as
> specified in
> > +      <a href='
> https://github.com/riscv-non-isa/rvv-intrinsic-doc/pull/234'>
> > +      RISC-V vector intrinsic specification</a>, thanks to Feng Wang et
> al.
> > +      from <a href="https://eswincomputing.com/">ESWIN
> Computing</a></li>
> > +  <li>Support for the T-head vector intrinsics.</li>
> > +  <li>Support for the scalar bitmanip and scalar crypto  intrinsics,
> thanks to
> > +      Liao Shihua from <a href="https://plctlab.org/">PLCT</a>.</li>
> > +  <li>Support for the large code model via option
> <code>-mcmodel=large</code>,
> > +      thanks to Kuan-Lin Chen from
> > +      <a href="https://www.andestech.com/">Andes Technology</a>.</li>
> > +  <li>Support for the standard vector calling convention variant,
> thanks to
> > +      Lehua Ding from <a href='https://rivai-ic.com.cn/
> '>RiVAI</a>.</li>
> > +  <li>Supports the <code>target</code> attribute, which allows users to
> compile
> > +      a function with specific extensions.</li>
> > +  <li><code>-march=</code> option no longer requires the architecture
> string
> > +      to be in canonical order, with only a few constraints remaining:
> the
> > +      architecture string must start with
> <code>rv[32|64][i|g|e]</code>, and
> > +      must use an underscore as the separator after a multi-letter
> extension.
> > +  </li>
> > +  <li><code>-march=help</code> option has been introduced to dump all
> > +      supported extensions.</li>
> > +  <li>Added experimental support for the
> <code>-mrvv-vector-bits=zvl</code>
> > +      option and the <code>riscv_rvv_vector_bits</code> attribute, which
> > +      specify a fixed length for scalable vector types. This option is
> > +      optimized for specific vector core implementations; however, the
> code
> > +      generated with this option is NOT portable,
>
> IIUC the code is just optimized for a specific vector length, not any
> specific core.  It's portable to other cores, just not portable to cores
> with different vector lengths.
>
> So I think we can soften the language a bit there, as it's not like
> we're emitting vendor-specific code on this one.
>
> > +      thanks to Pan Li from <a href="https://www.intel.com/">Intel</a>.
> > +  </li>
> > +  <li>Support for TLS descriptors has been introduced, which can be
> enabled by
> > +      the <code>-mtls-dialect=desc</code> option. The default behavior
> can be
> > +      configured with <code>--with-tls=[trad|desc]</code>.</li>
> > +  <li>Support for the TLS descriptors, this can be enabled by
> > +      <code>-mtls-dialect=desc</code> and the default behavior can be
> configure
> > +      by <code>--with-tls=[trad|desc], thanks to Tatsuyuki Ishi from
> > +      <a href="https://bluewhale.systems/">Blue Whale
> Systems</a></code>
>
> Maybe should call out that this will require the next glibc release to
> function correctly?
>
> > +  </li>
> > +  <li>Support for the following standard extensions has been added:
> > +    <ul>
> > +      <li>Vector crypto extensions:
> > +     <ul>
> > +       <li>Zvbb</li>
> > +       <li>Zvkb</li>
> > +       <li>Zvbc</li>
> > +       <li>Zvkg</li>
> > +       <li>Zvkned</li>
> > +       <li>Zvkhna</li>
> > +       <li>Zvkhnb</li>
> > +       <li>Zvksed</li>
> > +       <li>Zvksh</li>
> > +       <li>Zvkn</li>
> > +       <li>Zvknc</li>
> > +       <li>Zvkng</li>
> > +       <li>Zvks</li>
> > +       <li>Zvksc</li>
> > +       <li>Zvksg</li>
> > +       <li>Zvkt</li>
> > +     </ul>
> > +      </li>
> > +      <li>Code size reduction extensions:
> > +     <ul>
> > +       <li>Zca</li>
> > +       <li>Zcb</li>
> > +       <li>Zce</li>
> > +       <li>Zcf</li>
> > +       <li>Zcd</li>
> > +       <li>Zcmp</li>
> > +       <li>Zcmt</li>
> > +     </ul>
> > +      </li>
> > +      <li>Zicond</li>
> > +      <li>Zfa</li>
> > +      <li>Ztso</li>
> > +      <li>Zvfbfmin</li>
> > +      <li>Zvfhmin</li>
> > +      <li>Zvfh</li>
> > +      <li>Za64rs</li>
> > +      <li>Za128rs</li>
> > +      <li>Ziccif</li>
> > +      <li>Ziccrse</li>
> > +      <li>Ziccamoa</li>
> > +      <li>Zicclsm</li>
> > +      <li>Zic64b</li>
> > +      <li>Smaia</li>
> > +      <li>Smepmp</li>
> > +      <li>Smstateen</li>
> > +      <li>Ssaia</li>
> > +      <li>Sscofpmf</li>
> > +      <li>Ssstateen</li>
> > +      <li>Sstc</li>
> > +      <li>Svinval</li>
> > +      <li>Svnapot</li>
> > +      <li>Svpbmt</li>
> > +    </ul>
> > +  </li>
> > +  <li>Support for the following vendor extensions has been added:
> > +    <ul>
> > +      <li>T-Head:
> > +     <ul>
> > +       <li>XTheadVector</li>
> > +     </ul>
> > +      </li>
> > +      <li>CORE-V:
> > +     <ul>
> > +       <li>XCVmac</li>
> > +       <li>XCValu</li>
> > +       <li>XCVelw</li>
> > +       <li>XCVsimd</li>
> > +       <li>XCVbi</li>
> > +     </ul>
> > +      </li>
> > +      <li>Ventana Micro:
> > +     <ul>
> > +       <li>XVentanaCondops</li>
> > +     </ul>
> > +      </li>
> > +    </ul>
> > +  </li>
> > +  <li>The following new CPUs are supported through the
> <code>-mcpu</code>
> > +      option (GCC identifiers in parentheses).
> > +    <ul>
> > +      <li>SiFive's X280 (<code>sifive-x280</code>).</li>
> > +      <li>SiFive's P450 (<code>sifive-p450</code>).</li>
> > +      <li>SiFive's P670 (<code>sifive-p670</code>).</li>
> > +    </ul>
> > +  </li>
> > +  <li>The following new CPUs are supported through the
> <code>-mtune</code>
> > +      option (GCC identifiers in parentheses).
> > +    <ul>
> > +      <li>Generic out-of-order core (<code>generic-ooo</code>).</li>
> > +      <li>SiFive's P400 series (<code>sifive-p400-series</code>).</li>
> > +      <li>SiFive's P600 series (<code>sifive-p600-series</code>).</li>
> > +      <li>XiangShan's Nanhu microarchitecture
> (<code>xiangshan-nanhu</code>).</li>
> > +    </ul>
> > +  </li>
> > +</ul>
> >
> >  <!-- <h3 id="rx">RX</h3> -->
>
> Thanks for doing this.  This all pretty minor wording stuff, so
>
> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com>
> Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
>
> Maybe next year we'll remember to ask submitters for these ;)
>