[PATCH] D96518: [MIRLangRef] Document MachineOperand comments

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer created this revision.
SjoerdMeijer added reviewers: dmgreen, fhahn.
Herald added a subscriber: jdoerfert.
SjoerdMeijer requested review of this revision.
Herald added a project: LLVM.

Late follow-up of D74306 <https://reviews.llvm.org/D74306> to document MachineOperand comments in MIRLangRef.


https://reviews.llvm.org/D96518

Files:
  llvm/docs/MIRLangRef.rst


Index: llvm/docs/MIRLangRef.rst
===================================================================
--- llvm/docs/MIRLangRef.rst
+++ llvm/docs/MIRLangRef.rst
@@ -506,6 +506,24 @@
 
 .. TODO: Describe the FPIMM immediate operands.
 
+Comments
+^^^^^^^^
+
+Machine operands can have C/C++ style comments, which are annotations enclosed
+between ``/*`` and ``*/`` to improve readability of e.g. immediate operands.
+In the example below, ARM instructions EOR and BCC and immediate operands
+``14`` and ``0`` have been annotated with their condition codes (CC)
+definitions, i.e. the ``always`` and ``eq`` condition codes:
+
+.. code-block:: text
+
+  dead renamable $r2, $cpsr = tEOR killed renamable $r2, renamable $r1, 14 /* CC::always */, $noreg
+  t2Bcc %bb.4, 0 /* CC:eq */, killed $cpsr
+
+As these annotations are comments, they are ignored by the MI parser.
+Comments can be added or customized by overriding InstrInfo's hook
+``createMIROperandComment()``.
+
 .. _register-operands:
 
 Register Operands


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