[PATCH] D86637: [LangRef] get.active.lane.mask can produce poison

[Sjoerd Meijer via Phabricator via llvm-commits]

SjoerdMeijer created this revision.
SjoerdMeijer added reviewers: efriedma, simoll, samparker, fhahn, dmgreen.
Herald added a reviewer: jdoerfert.
Herald added a project: LLVM.
SjoerdMeijer requested review of this revision.

We had already specified that second argument `n` of this intrinsic is `n > 0`, but now add to this that the result is a poison value if this is not the case.


https://reviews.llvm.org/D86637

Files:
  llvm/docs/LangRef.rst


Index: llvm/docs/LangRef.rst
===================================================================
--- llvm/docs/LangRef.rst
+++ llvm/docs/LangRef.rst
@@ -16936,9 +16936,9 @@
 indexed by ``i``,  and ``%base``, ``%n`` are the two arguments to
 ``llvm.get.active.lane.mask.*``, ``%icmp`` is an integer compare and ``ult``
 the unsigned less-than comparison operator.  Overflow cannot occur in
-``(%base + i)`` and its comparison against ``%n`` with ``%n > 0``, as it is
-performed in integer numbers and not in machine numbers. The above is
-equivalent to:
+``(%base + i)`` and its comparison against ``%n`` as it is
+performed in integer numbers and not in machine numbers.  If ``%n`` is ``0``,
+then the result a poison value. The above is equivalent to:
 
 ::
 


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