Changes in directory llvm/docs:
ExtendingLLVM.html updated: 1.21 -> 1.22 --- Log message: Add a couple very minor tweaks --- Diffs of the changes: (+12 -8) ExtendingLLVM.html | 20 ++++++++++++-------- 1 files changed, 12 insertions(+), 8 deletions(-) Index: llvm/docs/ExtendingLLVM.html diff -u llvm/docs/ExtendingLLVM.html:1.21 llvm/docs/ExtendingLLVM.html:1.22 --- llvm/docs/ExtendingLLVM.html:1.21 Mon Jan 16 01:54:23 2006 +++ llvm/docs/ExtendingLLVM.html Mon Jan 16 10:31:40 2006 @@ -26,7 +26,8 @@ <div class="doc_author"> <p>Written by <a href="http://misha.brukman.net";>Misha Brukman</a>, - Brad Jones, and <a href="http://nondot.org/sabre";>Chris Lattner</a></p> + Brad Jones, Nate Begeman, + and <a href="http://nondot.org/sabre";>Chris Lattner</a></p> </div> <!-- *********************************************************************** --> @@ -123,7 +124,8 @@ code in all cases, just emit the expansion in <tt>visitCallInst</tt> in <tt>Writer.cpp</tt>. If the intrinsic has some way to express it with GCC (or any other compiler) extensions, it can be conditionally supported based on -the compiler compiling the CBE output (see llvm.prefetch for an example). +the compiler compiling the CBE output (see <tt>llvm.prefetch</tt> for an +example). Third, if the intrinsic really has no way to be lowered, just have the code generator emit code that prints an error message and calls abort if executed. </dd> @@ -136,13 +138,14 @@ code, you will likely need to add support for your intrinsic there as well. This is usually accomplished by adding a new node, and then teaching the SelectionDAG code how to handle that node. To do this, follow the steps in -the next section, Adding a new SelectionDAG node.</dd> +the <a href="#sdnode">Adding a new SelectionDAG node</a> section.</dd> <dl> <dt>Once you have added the new node, add code to <tt>SelectionDAG/SelectionDAGISel.cpp</tt> to recognize the intrinsic. In most cases, the intrinsic will just be turned into the node you just added. For an -example of this, see how <tt>visitIntrinsicCall</tt> handles Intrinsic::ctpop +example of this, see how <tt>visitIntrinsicCall</tt> handles +<tt>Intrinsic::ctpop_*</tt>. </dt> </div> @@ -182,14 +185,15 @@ targets supported by the SelectionDAG framework will natively support the new node. In this case, you must also add code in your node's case statement in <tt>LegalizeOp</tt> to Expand your node into simpler, legal - operations. The case for ISD::UREM for expanding a remainder into a - multiply and a subtract is a good example.</li> + operations. The case for <tt>ISD::UREM</tt> for expanding a remainder into + a divide, multiply, and a subtract is a good example.</li> <li><tt>lib/CodeGen/SelectionDAG/LegalizeDAG.cpp</tt>: If targets may support the new node being added only at certain sizes, you will also need to add code to your node's case statement in <tt>LegalizeOp</tt> to Promote your node's operands to a larger size, and perform the correct operation. You will also need to add code to - <tt>PromoteOp</tt> to do this as well. For a good example, see ISD::BSWAP, + <tt>PromoteOp</tt> to do this as well. For a good example, see + <tt>ISD::BSWAP</tt>, which promotes its operand to a wider size, performs the byteswap, and then shifts the correct bytes right to emulate the narrower byteswap in the wider type.</li> @@ -401,7 +405,7 @@ <a href="http://llvm.cs.uiuc.edu";>The LLVM Compiler Infrastructure</a> <br> - Last modified: $Date: 2006/01/16 07:54:23 $ + Last modified: $Date: 2006/01/16 16:31:40 $ </address> </body> _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
