[PGO] Update VP metadata after memory intrinsic optimization

Summary:
Leave an updated VP metadata on the fallback memcpy intrinsic after
specialization. This can be used for later possible expansion based on
the average of the remaining values.

Reviewers: davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D34164

llvm-svn: 305321

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp b/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
index 96027bc3d0a..39a3ef2a49a 100644
--- a/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
+++ b/llvm/lib/Transforms/Instrumentation/IndirectCallPromotion.cpp
@@ -884,6 +884,7 @@ bool MemOPSizeOpt::perform(MemIntrinsic *MI) {
 
   // Keeping track of the count of the default case:
   uint64_t RemainCount = TotalCount;
+  uint64_t SavedRemainCount = SavedTotalCount;
   SmallVector<uint64_t, 16> SizeIds;
   SmallVector<uint64_t, 16> CaseCounts;
   uint64_t MaxCount = 0;
@@ -912,6 +913,8 @@ bool MemOPSizeOpt::perform(MemIntrinsic *MI) {
 
     assert(RemainCount >= C);
     RemainCount -= C;
+    assert(SavedRemainCount >= VD.Count);
+    SavedRemainCount -= VD.Count;
 
     if (++Version > MemOPMaxVersion && MemOPMaxVersion != 0)
       break;
@@ -968,6 +971,11 @@ bool MemOPSizeOpt::perform(MemIntrinsic *MI) {
 
   // Clear the value profile data.
   MI->setMetadata(LLVMContext::MD_prof, nullptr);
+  // If all promoted, we don't need the MD.prof metadata.
+  if (SavedRemainCount > 0 || Version != NumVals)
+    // Otherwise we need update with the un-promoted records back.
+    annotateValueSite(*Func.getParent(), *MI, VDs.slice(Version),
+                      SavedRemainCount, IPVK_MemOPSize, NumVals);
 
   DEBUG(dbgs() << "\n\n== Basic Block After==\n");