Add initial support for the convergent attribute.

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

diff --git a/docs/LangRef.rst b/docs/LangRef.rst
index 48ac8fbc7db3754a28f959e2f41570b71d2d8c3d..397d5fe3756734dfddf4f49209952b3f757878f4 100644 (file)
--- a/docs/LangRef.rst
+++ b/docs/LangRef.rst
@@ -1196,6 +1196,13 @@ example:
     computing edge weights, basic blocks post-dominated by a cold
     function call are also considered to be cold; and, thus, given low
     weight.
+``convergent``
+    This attribute indicates that the callee is dependent on a convergent
+    thread execution pattern under certain parallel execution models.
+    Transformations that are execution model agnostic may only move or
+    tranform this call if the final location is control equivalent to its
+    original position in the program, where control equivalence is defined as
+    A dominates B and B post-dominates A, or vice versa.
 ``inlinehint``
     This attribute indicates that the source code contained a hint that
     inlining this function is desirable (such as the "inline" keyword in
@@ -5658,7 +5665,7 @@ Syntax:
 
 ::
 
-      <result> = load [volatile] <ty>, <ty>* <pointer>[, align <alignment>][, !nontemporal !<index>][, !invariant.load !<index>][, !nonnull !<index>]
+      <result> = load [volatile] <ty>, <ty>* <pointer>[, align <alignment>][, !nontemporal !<index>][, !invariant.load !<index>][, !nonnull !<index>][, !dereferenceable !<index>][, !dereferenceable_or_null !<index>]
       <result> = load atomic [volatile] <ty>* <pointer> [singlethread] <ordering>, align <alignment>
       !<index> = !{ i32 1 }
 
@@ -5723,6 +5730,25 @@ never be null.  This is analogous to the ''nonnull'' attribute
 on parameters and return values.  This metadata can only be applied
 to loads of a pointer type.
 
+The optional ``!dereferenceable`` metadata must reference a single
+metadata name ``<index>`` corresponding to a metadata node with one ``i64``
+entry. The existence of the ``!dereferenceable`` metadata on the instruction 
+tells the optimizer that the value loaded is known to be dereferenceable.
+The number of bytes known to be dereferenceable is specified by the integer 
+value in the metadata node. This is analogous to the ''dereferenceable'' 
+attribute on parameters and return values.  This metadata can only be applied 
+to loads of a pointer type.
+
+The optional ``!dereferenceable_or_null`` metadata must reference a single
+metadata name ``<index>`` corresponding to a metadata node with one ``i64``
+entry. The existence of the ``!dereferenceable_or_null`` metadata on the 
+instruction tells the optimizer that the value loaded is known to be either
+dereferenceable or null.
+The number of bytes known to be dereferenceable is specified by the integer 
+value in the metadata node. This is analogous to the ''dereferenceable_or_null'' 
+attribute on parameters and return values.  This metadata can only be applied 
+to loads of a pointer type.
+
 Semantics:
 """"""""""