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[oota-llvm.git] / docs / AliasAnalysis.html

diff --git a/docs/AliasAnalysis.html b/docs/AliasAnalysis.html
index 591694a983cf3513c76f540d8a68bf43de0d93d7..8fbb29f818a36061eaa945bf597af5639dd7d909 100644 (file)
--- a/docs/AliasAnalysis.html
+++ b/docs/AliasAnalysis.html
@@ -117,6 +117,11 @@ as the actual <tt>call</tt> or <tt>invoke</tt> instructions that performs the
 call.  The <tt>AliasAnalysis</tt> interface also exposes some helper methods
 which allow you to get mod/ref information for arbitrary instructions.</p>
 
+<p>All <tt>AliasAnalysis</tt> interfaces require that in queries involving
+multiple values, values which are not
+<a href="LangRef.html#constants">constants</a> are all defined within the
+same function.</p>
+
 </div>
 
 <!-- ======================================================================= -->
@@ -181,9 +186,14 @@ that the accesses alias.</p>
 </div>
   
 <div class="doc_text">
-The <tt>alias</tt> method is the primary interface used to determine whether or
-not two memory objects alias each other.  It takes two memory objects as input
-and returns MustAlias, MayAlias, or NoAlias as appropriate.
+<p>The <tt>alias</tt> method is the primary interface used to determine whether
+or not two memory objects alias each other.  It takes two memory objects as
+input and returns MustAlias, PartialAlias, MayAlias, or NoAlias as
+appropriate.</p>
+
+<p>Like all <tt>AliasAnalysis</tt> interfaces, the <tt>alias</tt> method requires
+that either the two pointer values be defined within the same function, or at
+least one of the values is a <a href="LangRef.html#constants">constant</a>.</p>
 </div>
 
 <!-- _______________________________________________________________________ -->
@@ -202,13 +212,14 @@ the other -- in this case, there is a dependence, but it's mediated by the free
 and reallocation.</p>
 
 <p>As an exception to this is with the
-<a href="LangRef.html#noalias"><tt>noalias</tt></a> keyword. AliasAnalysis
-implementations may choose to ignore the "irrelevant" dependencies, provided
-their clients do not need to be aware of these dependencies for correctness.</p>
+<a href="LangRef.html#noalias"><tt>noalias</tt></a> keyword; the "irrelevant"
+dependencies are ignored.</p>
 
 <p>The MayAlias response is used whenever the two pointers might refer to the
-same object.  If the two memory objects overlap, but do not start at the same
-location, return MayAlias.</p>
+same object.</p>
+
+<p>The PartialAlias response is used when the two memory objects are known
+to be overlapping in some way, but do not start at the same address.</p>
 
 <p>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
@@ -230,10 +241,10 @@ a location, ModRef is returned.</p>
 
 <p>The <tt>AliasAnalysis</tt> class also provides a <tt>getModRefInfo</tt>
 method for testing dependencies between function calls.  This method takes two
-call sites (CS1 &amp; CS2), returns NoModRef if the two calls refer to disjoint
-memory locations, Ref if CS1 reads memory written by CS2, Mod if CS1 writes to
-memory read or written by CS2, or ModRef if CS1 might read or write memory
-accessed by CS2.  Note that this relation is not commutative.</p>
+call sites (CS1 &amp; CS2), returns NoModRef if neither call writes to memory
+read or written by the other, Ref if CS1 reads memory written by CS2, Mod if CS1
+writes to memory read or written by CS2, or ModRef if CS1 might read or write
+memory written to by CS2.  Note that this relation is not commutative.</p>
 
 </div>
 
@@ -705,8 +716,8 @@ problem.</p>
 
 <div class="doc_text">
 
-<p>The <tt>-basicaa</tt> pass is the default LLVM alias analysis.  It is an
-aggressive local analysis that "knows" many important facts:</p>
+<p>The <tt>-basicaa</tt> pass is an aggressive local analysis that "knows"
+many important facts:</p>
 
 <ul>
 <li>Distinct globals, stack allocations, and heap allocations can never