Add function entry counts from sample profiles.

This patch uses the new function profile metadata "function_entry_count"
to annotate entry counts from sample profiles.

In a sampling profile, the total samples collected at the function entry
are an approximation for the number of times that function was invoked.

llvm-svn: 237265

1 files changed, 4 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/SampleProfile.cpp b/llvm/lib/Transforms/Scalar/SampleProfile.cpp
index 594a7beb2e3..3480cd49912 100644
--- a/llvm/lib/Transforms/Scalar/SampleProfile.cpp
+++ b/llvm/lib/Transforms/Scalar/SampleProfile.cpp
@@ -580,6 +580,10 @@ void SampleProfileLoader::propagateWeights(Function &F) {
   bool Changed = true;
   unsigned i = 0;
 
+  // Add an entry count to the function using the samples gathered
+  // at the function entry.
+  F.setEntryCount(Samples->getHeadSamples());
+
   // Before propagation starts, build, for each block, a list of
   // unique predecessors and successors. This is necessary to handle
   // identical edges in multiway branches. Since we visit all blocks and all