Add more documentation mentioning the limitations due to PR2660.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62919 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LangRef.html b/docs/LangRef.html
index f2d7d8d..35f83b4 100644
--- a/docs/LangRef.html
+++ b/docs/LangRef.html
@@ -1344,6 +1344,13 @@
</tr>
</tbody>
</table>
+
+<p>Note that the code generator does not yet support large integer types
+to be used as function return types. The specific limit on how large a
+return type the code generator can currently handle is target-dependent;
+currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
+targets.</p>
+
</div>
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@@ -1404,6 +1411,11 @@
length. This allows implementation of 'pascal style arrays' with the LLVM
type "{ i32, [0 x float]}", for example.</p>
+<p>Note that the code generator does not yet support large aggregate types
+to be used as function return types. The specific limit on how large an
+aggregate return type the code generator can currently handle is
+target-dependent, and also dependent on the aggregate element types.</p>
+
</div>
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@@ -1489,6 +1501,12 @@
an <tt>i32</tt>.</td>
</tr>
</table>
+
+<p>Note that the code generator does not yet support large aggregate types
+to be used as function return types. The specific limit on how large an
+aggregate return type the code generator can currently handle is
+target-dependent, and also dependent on the aggregate element types.</p>
+
</div>
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@@ -1593,6 +1611,12 @@
<td class="left">Vector of 2 64-bit integer values.</td>
</tr>
</table>
+
+<p>Note that the code generator does not yet support large vector types
+to be used as function return types. The specific limit on how large a
+vector return type codegen can currently handle is target-dependent;
+currently it's often a few times longer than a hardware vector register.</p>
+
</div>
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@@ -2042,8 +2066,13 @@
ret { i32, i8 } { i32 4, i8 2 } <i>; Return an aggregate of values 4 and 2</i>
</pre>
-<p>Note that the code generator does not yet fully support larger
- aggregate return values.</p>
+<p>Note that the code generator does not yet fully support large
+ return values. The specific sizes that are currently supported are
+ dependent on the target. For integers, on 32-bit targets the limit
+ is often 64 bits, and on 64-bit targets the limit is often 128 bits.
+ For aggregate types, the current limits are dependent on the element
+ types; for example targets are often limited to 2 total integer
+ elements and 2 total floating-point elements.</p>
</div>
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