Add bogus conditional branch before stlx

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

diff --git a/docs/BranchWeightMetadata.rst b/docs/BranchWeightMetadata.rst
index aff7923d18656d4531208c9e0afefabf8fbc0a11..6cbcb0f0fb241e12a7dabdc2eb20ac0b3090dcbc 100644 (file)
--- a/docs/BranchWeightMetadata.rst
+++ b/docs/BranchWeightMetadata.rst
@@ -27,7 +27,7 @@ Supported Instructions
 ^^^^^^^^^^^^^^
 
 Metadata is only assigned to the conditional branches. There are two extra
-operarands for the true and the false branch.
+operands for the true and the false branch.
 
 .. code-block:: llvm
 
@@ -114,4 +114,27 @@ CFG Modifications
 
 Branch Weight Metatada is not proof against CFG changes. If terminator operands'
 are changed some action should be taken. In other case some misoptimizations may
-occur due to incorrent branch prediction information.
+occur due to incorrect branch prediction information.
+
+Function Entry Counts
+=====================
+
+To allow comparing different functions during inter-procedural analysis and
+optimization, ``MD_prof`` nodes can also be assigned to a function definition.
+The first operand is a string indicating the name of the associated counter.
+
+Currently, one counter is supported: "function_entry_count". This is a 64-bit
+counter that indicates the number of times that this function was invoked (in
+the case of instrumentation-based profiles). In the case of sampling-based
+profiles, this counter is an approximation of how many times the function was
+invoked.
+
+For example, in the code below, the instrumentation for function foo()
+indicates that it was called 2,590 times at runtime.
+
+.. code-block:: llvm
+
+  define i32 @foo() !prof !1 {
+    ret i32 0
+  }
+  !1 = !{!"function_entry_count", i64 2590}