Add a note about the V9 backend.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13959 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/CodeGenerator.html b/docs/CodeGenerator.html
index b0ed049..f7d904c 100644
--- a/docs/CodeGenerator.html
+++ b/docs/CodeGenerator.html
@@ -130,6 +130,18 @@
make use of any of the built-in components. Doing so is not recommended at all,
but could be required for radically different targets that do not fit into the
LLVM machine description model: programmable FPGAs for example.</p>
+
+<p><b>Important Note:</b> For historical reasons, the LLVM SparcV9 code
+generator uses almost entirely different code paths than described in this
+document. For this reason, there are some deprecated interfaces (such as
+<tt>TargetRegInfo</tt> and <tt>TargetSchedInfo</tt>), which are only used by the
+V9 backend and should not be used by any other targets. Also, all code in the
+<tt>lib/Target/SparcV9</tt> directory and subdirectories should be considered
+deprecated, and should not be used as the basis for future code generator work.
+The SparcV9 backend is slowly being merged into the rest of the target
+independent code generators, but this is a low-priority process with no
+predictable completion date.</p>
+
</div>
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