4 files changed, 76 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/Analysis.cpp b/llvm/lib/Analysis/Analysis.cpp
index 099ac15245c..2bcfe402e68 100644
--- a/llvm/lib/Analysis/Analysis.cpp
+++ b/llvm/lib/Analysis/Analysis.cpp
@@ -54,6 +54,7 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializeIVUsersPass(Registry);
   initializeInstCountPass(Registry);
   initializeIntervalPartitionPass(Registry);
+  initializeLazyBlockFrequencyInfoPassPass(Registry);
   initializeLazyValueInfoWrapperPassPass(Registry);
   initializeLintPass(Registry);
   initializeLoopInfoWrapperPassPass(Registry);
diff --git a/llvm/lib/Analysis/BlockFrequencyInfo.cpp b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
index de1c8553c93..1dd8f4fdfcf 100644
--- a/llvm/lib/Analysis/BlockFrequencyInfo.cpp
+++ b/llvm/lib/Analysis/BlockFrequencyInfo.cpp
@@ -129,6 +129,12 @@ BlockFrequencyInfo &BlockFrequencyInfo::operator=(BlockFrequencyInfo &&RHS) {
   return *this;
 }
 
+// Explicitly define the default constructor otherwise it would be implicitly
+// defined at the first ODR-use which is the BFI member in the
+// LazyBlockFrequencyInfo header.  The dtor needs the BlockFrequencyInfoImpl
+// template instantiated which is not available in the header.
+BlockFrequencyInfo::~BlockFrequencyInfo() {}
+
 void BlockFrequencyInfo::calculate(const Function &F,
                                    const BranchProbabilityInfo &BPI,
                                    const LoopInfo &LI) {
diff --git a/llvm/lib/Analysis/CMakeLists.txt b/llvm/lib/Analysis/CMakeLists.txt
index ee9edd8b01a..5c6011d77ce 100644
--- a/llvm/lib/Analysis/CMakeLists.txt
+++ b/llvm/lib/Analysis/CMakeLists.txt
@@ -37,6 +37,7 @@ add_llvm_library(LLVMAnalysis
   Interval.cpp
   IntervalPartition.cpp
   IteratedDominanceFrontier.cpp
+  LazyBlockFrequencyInfo.cpp
   LazyCallGraph.cpp
   LazyValueInfo.cpp
   Lint.cpp
diff --git a/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp b/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp
new file mode 100644
index 00000000000..7debfde87d2
--- /dev/null
+++ b/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp
@@ -0,0 +1,68 @@
+//===- LazyBlockFrequencyInfo.cpp - Lazy Block Frequency Analysis ---------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This is an alternative analysis pass to BlockFrequencyInfoWrapperPass.  The
+// difference is that with this pass the block frequencies are not computed when
+// the analysis pass is executed but rather when the BFI results is explicitly
+// requested by the analysis client.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/LoopInfo.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "lazy-block-freq"
+
+INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
+                      "Lazy Block Frequency Analysis", true, true)
+INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
+                    "Lazy Block Frequency Analysis", true, true)
+
+char LazyBlockFrequencyInfoPass::ID = 0;
+
+LazyBlockFrequencyInfoPass::LazyBlockFrequencyInfoPass() : FunctionPass(ID) {
+  initializeLazyBlockFrequencyInfoPassPass(*PassRegistry::getPassRegistry());
+}
+
+void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const {
+  LBFI.getCalculated().print(OS);
+}
+
+void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  AU.addRequired<LoopInfoWrapperPass>();
+  AU.setPreservesAll();
+}
+
+void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); }
+
+bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) {
+  BranchProbabilityInfo &BPI =
+      getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
+  LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+  LBFI.setAnalysis(&F, &BPI, &LI);
+  return false;
+}
+
+void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) {
+  AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  AU.addRequired<LazyBlockFrequencyInfoPass>();
+  AU.addRequired<LoopInfoWrapperPass>();
+}
+
+void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) {
+  INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass);
+  INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass);
+  INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
+}