From 50f10eb432f6f6d75a8a477b826ee2621c3d553f Mon Sep 17 00:00:00 2001
From: Juergen Ributzka <juergen@apple.com>
Date: Tue, 9 Dec 2014 16:36:06 +0000
Subject: [PATCH] Move function to obtain branch weights into the BranchInst
 class. NFC.

Make this function available to other parts of LLVM.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223784 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/IR/Instructions.h       |  4 ++++
 lib/IR/Instructions.cpp              | 20 +++++++++++++++++
 lib/Transforms/Utils/SimplifyCFG.cpp | 32 ++++++----------------------
 3 files changed, 30 insertions(+), 26 deletions(-)

diff --git a/include/llvm/IR/Instructions.h b/include/llvm/IR/Instructions.h
index dcf19e0972d..5157ca6f447 100644
--- a/include/llvm/IR/Instructions.h
+++ b/include/llvm/IR/Instructions.h
@@ -2535,6 +2535,10 @@ public:
   /// continues to map correctly to each operand.
   void swapSuccessors();
 
+  /// \brief Retrieve the probabilities of a conditional branch. Returns true on
+  /// success, or returns false if no or invalid metadata was found.
+  bool getBranchWeights(uint64_t &TrueWeight, uint64_t &FalseWeight) const;
+
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const Instruction *I) {
     return (I->getOpcode() == Instruction::Br);
diff --git a/lib/IR/Instructions.cpp b/lib/IR/Instructions.cpp
index f4c6a289b80..5ea45357864 100644
--- a/lib/IR/Instructions.cpp
+++ b/lib/IR/Instructions.cpp
@@ -805,6 +805,26 @@ void BranchInst::swapSuccessors() {
               MDNode::get(ProfileData->getContext(), Ops));
 }
 
+bool BranchInst::getBranchWeights(uint64_t &TrueWeight,
+                                  uint64_t &FalseWeight) const {
+  if (isUnconditional())
+    return false;
+
+  auto *MD = getMetadata(LLVMContext::MD_prof);
+  if (!MD || MD->getNumOperands() != 3)
+    return false;
+
+  auto *TrueCI = dyn_cast<ConstantInt>(MD->getOperand(1));
+  auto *FalseCI = dyn_cast<ConstantInt>(MD->getOperand(2));
+  if (!TrueCI || !FalseCI)
+    return false;
+
+  TrueWeight = TrueCI->getValue().getZExtValue();
+  FalseWeight = FalseCI->getValue().getZExtValue();
+
+  return true;
+}
+
 BasicBlock *BranchInst::getSuccessorV(unsigned idx) const {
   return getSuccessor(idx);
 }
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index daa576cfbdc..3efb89a4d7f 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2027,24 +2027,6 @@ static bool SimplifyCondBranchToTwoReturns(BranchInst *BI,
   return true;
 }
 
-/// ExtractBranchMetadata - Given a conditional BranchInstruction, retrieve the
-/// probabilities of the branch taking each edge. Fills in the two APInt
-/// parameters and return true, or returns false if no or invalid metadata was
-/// found.
-static bool ExtractBranchMetadata(BranchInst *BI,
-                                  uint64_t &ProbTrue, uint64_t &ProbFalse) {
-  assert(BI->isConditional() &&
-         "Looking for probabilities on unconditional branch?");
-  MDNode *ProfileData = BI->getMetadata(LLVMContext::MD_prof);
-  if (!ProfileData || ProfileData->getNumOperands() != 3) return false;
-  ConstantInt *CITrue = dyn_cast<ConstantInt>(ProfileData->getOperand(1));
-  ConstantInt *CIFalse = dyn_cast<ConstantInt>(ProfileData->getOperand(2));
-  if (!CITrue || !CIFalse) return false;
-  ProbTrue = CITrue->getValue().getZExtValue();
-  ProbFalse = CIFalse->getValue().getZExtValue();
-  return true;
-}
-
 /// checkCSEInPredecessor - Return true if the given instruction is available
 /// in its predecessor block. If yes, the instruction will be removed.
 ///
@@ -2250,10 +2232,10 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, const DataLayout *DL,
       PBI->setCondition(NewCond);
 
       uint64_t PredTrueWeight, PredFalseWeight, SuccTrueWeight, SuccFalseWeight;
-      bool PredHasWeights = ExtractBranchMetadata(PBI, PredTrueWeight,
-                                                  PredFalseWeight);
-      bool SuccHasWeights = ExtractBranchMetadata(BI, SuccTrueWeight,
-                                                  SuccFalseWeight);
+      bool PredHasWeights =
+          PBI->getBranchWeights(PredTrueWeight, PredFalseWeight);
+      bool SuccHasWeights =
+          BI->getBranchWeights(SuccTrueWeight, SuccFalseWeight);
       SmallVector<uint64_t, 8> NewWeights;
 
       if (PBI->getSuccessor(0) == BB) {
@@ -2523,10 +2505,8 @@ static bool SimplifyCondBranchToCondBranch(BranchInst *PBI, BranchInst *BI) {
 
   // Update branch weight for PBI.
   uint64_t PredTrueWeight, PredFalseWeight, SuccTrueWeight, SuccFalseWeight;
-  bool PredHasWeights = ExtractBranchMetadata(PBI, PredTrueWeight,
-                                              PredFalseWeight);
-  bool SuccHasWeights = ExtractBranchMetadata(BI, SuccTrueWeight,
-                                              SuccFalseWeight);
+  bool PredHasWeights = PBI->getBranchWeights(PredTrueWeight, PredFalseWeight);
+  bool SuccHasWeights = BI->getBranchWeights(SuccTrueWeight, SuccFalseWeight);
   if (PredHasWeights && SuccHasWeights) {
     uint64_t PredCommon = PBIOp ? PredFalseWeight : PredTrueWeight;
     uint64_t PredOther = PBIOp ?PredTrueWeight : PredFalseWeight;
-- 
2.34.1