doc: update architectures on source install instructions

Fixes #16099

Change-Id: I334c1f04dfc98c4a07e33745819d890b5fcb1673
Reviewed-on: https://go-review.googlesource.com/24243
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

diff --git a/doc/install-source.html b/doc/install-source.html
index 1d7df3d42c9b62792f49884dd5efb0e57d207352..991be3f18212a21a688fb5004d25fe0c983596c8 100644 (file)
--- a/doc/install-source.html
+++ b/doc/install-source.html
@@ -33,7 +33,7 @@ compiler using the GCC back end, see
 </p>
 
 <p>
-The Go compilers support six instruction sets.
+The Go compilers support seven instruction sets.
 There are important differences in the quality of the compilers for the different
 architectures.
 </p>
@@ -43,15 +43,17 @@ architectures.
        <code>amd64</code> (also known as <code>x86-64</code>)
 </dt>
 <dd>
-       A mature implementation. The compiler has an effective
-       optimizer (registerizer) and generates good code (although
-       <code>gccgo</code> can do noticeably better sometimes).
+       A mature implementation. New in 1.7 is its SSA-based back end
+       that generates compact, efficient code.
 </dd>
 <dt>
        <code>386</code> (<code>x86</code> or <code>x86-32</code>)
 </dt>
 <dd>
-       Comparable to the <code>amd64</code> port.
+       Comparable to the <code>amd64</code> port, but does
+       not yet use the SSA-based back end. It has an effective
+       optimizer (registerizer) and generates good code (although
+       <code>gccgo</code> can do noticeably better sometimes).
 </dd>
 <dt>
        <code>arm</code> (<code>ARM</code>)
@@ -77,6 +79,12 @@ architectures.
 <dd>
        Supports Linux binaries. New in 1.6 and not as well exercised as other ports.
 </dd>
+<dt>
+       <code>s390x</code> (IBM System z)
+</dt>
+<dd>
+       Supports Linux binaries. New in 1.7 and not as well exercised as other ports.
+</dd>
 </dl>
 
 <p>