Switch the type field in DIVariable and DIGlobalVariable over to DITypeRefs.

[oota-llvm.git] / docs / WritingAnLLVMBackend.rst

diff --git a/docs/WritingAnLLVMBackend.rst b/docs/WritingAnLLVMBackend.rst
index 35c853e5ed0fb10414bf7dee53b0818c470dbc01..429f52a3526a6a1f1a9c2f215c80c07ed9cfcc97 100644 (file)
--- a/docs/WritingAnLLVMBackend.rst
+++ b/docs/WritingAnLLVMBackend.rst
@@ -238,6 +238,12 @@ For some targets, you also need to support the following methods:
 * ``getTargetLowering()``
 * ``getJITInfo()``
 
+Some architectures, such as GPUs, do not support jumping to an arbitrary
+program location and implement branching using masked execution and loop using
+special instructions around the loop body. In order to avoid CFG modifications
+that introduce irreducible control flow not handled by such hardware, a target
+must call `setRequiresStructuredCFG(true)` when being initialized.
+
 In addition, the ``XXXTargetMachine`` constructor should specify a
 ``TargetDescription`` string that determines the data layout for the target
 machine, including characteristics such as pointer size, alignment, and
@@ -976,6 +982,7 @@ operands:
 This results in:
 
 .. code-block:: c++
+
   namespace X86 {
   namespace OpTypes {
   enum OperandType {