Re-land "[ThinLTO] Add call edges' relative block frequency to per-module summary."
It was reverted after buildbot regressions.
Original commit message:
This allows relative block frequency of call edges to be passed
to the thinlink stage where it will be used to compute synthetic
entry counts of functions.
llvm-svn: 323460
diff --git a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
index cf2fe77..9293f60 100644
--- a/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
+++ b/llvm/lib/Analysis/ModuleSummaryAnalysis.cpp
@@ -273,9 +273,24 @@
// to record the call edge to the alias in that case. Eventually
// an alias summary will be created to associate the alias and
// aliasee.
- CallGraphEdges[Index.getOrInsertValueInfo(
- cast<GlobalValue>(CalledValue))]
- .updateHotness(Hotness);
+ auto &ValueInfo = CallGraphEdges[Index.getOrInsertValueInfo(
+ cast<GlobalValue>(CalledValue))];
+ ValueInfo.updateHotness(Hotness);
+ // Add the relative block frequency to CalleeInfo if there is no profile
+ // information.
+ if (BFI != nullptr && Hotness == CalleeInfo::HotnessType::Unknown) {
+ auto BBFreq = BFI->getBlockFreq(&BB).getFrequency();
+ // FIXME: This might need some scaling to prevent BBFreq values from
+ // being rounded down to 0.
+ auto EntryFreq = BFI->getEntryFreq();
+ // Block frequencies can be directly set for a block and so we need to
+ // handle the case of entry frequency being 0.
+ if (EntryFreq)
+ BBFreq /= EntryFreq;
+ else
+ BBFreq = 0;
+ ValueInfo.updateRelBlockFreq(BBFreq);
+ }
} else {
// Skip inline assembly calls.
if (CI && CI->isInlineAsm())