BlockFrequencyInfo: Add PrintBlockFreq helper (#67512)

- Refactor the (Machine)BlockFrequencyInfo::printBlockFreq functions
into a `PrintBlockFreq()` function returning a `Printable` object. This
simplifies usage as it can be directly piped to a `raw_ostream` like
`dbgs() << PrintBlockFreq(MBFI, Freq) << '\n';`.
- Previously there was an interesting behavior where
`BlockFrequencyInfoImpl` stores frequencies both as a `Scaled64` number
and as an `uint64_t`. Most algorithms use the `BlockFrequency`
abstraction with the integers, the print function for basic blocks
printed the `Scaled64` number potentially showing higher accuracy than
was used by the algorithm. This changes things to only print
`BlockFrequency` values.
- Replace some instances of `dbgs() << Freq.getFrequency()` with the new
function.

1 files changed, 12 insertions, 12 deletions

diff --git a/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp b/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
index a440079..6f94499 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfoImpl.cpp
@@ -640,19 +640,19 @@ BlockFrequencyInfoImplBase::getLoopName(const LoopData &Loop) const {
   return getBlockName(Loop.getHeader()) + (Loop.isIrreducible() ? "**" : "*");
 }
 
-raw_ostream &
-BlockFrequencyInfoImplBase::printBlockFreq(raw_ostream &OS,
-                                           const BlockNode &Node) const {
-  return OS << getFloatingBlockFreq(Node);
-}
-
-raw_ostream &
-BlockFrequencyInfoImplBase::printBlockFreq(raw_ostream &OS,
-                                           BlockFrequency Freq) const {
+void llvm::printBlockFreqImpl(raw_ostream &OS, BlockFrequency EntryFreq,
+                              BlockFrequency Freq) {
+  if (Freq == BlockFrequency(0)) {
+    OS << "0";
+    return;
+  }
+  if (EntryFreq == BlockFrequency(0)) {
+    OS << "<invalid BFI>";
+    return;
+  }
   Scaled64 Block(Freq.getFrequency(), 0);
-  Scaled64 Entry(getEntryFreq().getFrequency(), 0);
-
-  return OS << Block / Entry;
+  Scaled64 Entry(EntryFreq.getFrequency(), 0);
+  OS << Block / Entry;
 }
 
 void IrreducibleGraph::addNodesInLoop(const BFIBase::LoopData &OuterLoop) {