[PATCH] D31758: Invariant.group and mustalias docs fixes
Piotr Padlewski via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue Apr 11 02:17:44 PDT 2017
Prazek updated this revision to Diff 94798.
Prazek added a comment.
Sanjoy comments
https://reviews.llvm.org/D31758
Files:
docs/AliasAnalysis.rst
docs/LangRef.rst
Index: docs/LangRef.rst
===================================================================
--- docs/LangRef.rst
+++ docs/LangRef.rst
@@ -5118,6 +5118,16 @@
!0 = !{!"magic ptr"}
!1 = !{!"other ptr"}
+The invariant.group metadata must be dropped when replacing one pointer by
+another based on aliasing information. This is because invariant.group is tied
+to the SSA value of the pointer operand.
+
+.. code-block:: llvm
+ %v = load i8, i8* %x, !invariant.group !0
+ ; if %x mustalias %y then we can replace the above instruction with
+ %v = load i8, i8* %y
+
+
'``type``' Metadata
^^^^^^^^^^^^^^^^^^^
Index: docs/AliasAnalysis.rst
===================================================================
--- docs/AliasAnalysis.rst
+++ docs/AliasAnalysis.rst
@@ -136,7 +136,7 @@
The ``MustAlias`` response may only be returned if the two memory objects are
guaranteed to always start at exactly the same location. A ``MustAlias``
-response implies that the pointers compare equal.
+response does not imply that the pointers compare equal.
The ``getModRefInfo`` methods
-----------------------------
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