DenseMap::find_as() and unit tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149229 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 1 deletions

diff --git a/docs/ProgrammersManual.html b/docs/ProgrammersManual.html
index 51862034b7..0b1a875da1 100644
--- a/docs/ProgrammersManual.html
+++ b/docs/ProgrammersManual.html
@@ -1753,7 +1753,7 @@ pointers, or map other small types to each other.
 
 <p>
 There are several aspects of DenseMap that you should be aware of, however.  The
-iterators in a densemap are invalidated whenever an insertion occurs, unlike
+iterators in a DenseMap are invalidated whenever an insertion occurs, unlike
 map.  Also, because DenseMap allocates space for a large number of key/value
 pairs (it starts with 64 by default), it will waste a lot of space if your keys
 or values are large.  Finally, you must implement a partial specialization of
@@ -1761,6 +1761,14 @@ DenseMapInfo for the key that you want, if it isn't already supported.  This
 is required to tell DenseMap about two special marker values (which can never be
 inserted into the map) that it needs internally.</p>
 
+<p>
+DenseMap's find_as() method supports lookup operations using an alternate key
+type. This is useful in cases where the normal key type is expensive to
+construct, but cheap to compare against. The DenseMapInfo is responsible for
+defining the appropriate comparison and hashing methods for each alternate
+key type used.
+</p>
+
 </div>
 
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