4 files changed, 72 insertions, 8 deletions
diff --git a/llvm/lib/Analysis/Analysis.cpp b/llvm/lib/Analysis/Analysis.cpp
index c04447ca58c..d31adfa90ed 100644
--- a/llvm/lib/Analysis/Analysis.cpp
+++ b/llvm/lib/Analysis/Analysis.cpp
@@ -54,6 +54,7 @@ void llvm::initializeAnalysis(PassRegistry &Registry) {
   initializeIVUsersWrapperPassPass(Registry);
   initializeInstCountPass(Registry);
   initializeIntervalPartitionPass(Registry);
+  initializeLazyBranchProbabilityInfoPassPass(Registry);
   initializeLazyBlockFrequencyInfoPassPass(Registry);
   initializeLazyValueInfoWrapperPassPass(Registry);
   initializeLintPass(Registry);
diff --git a/llvm/lib/Analysis/CMakeLists.txt b/llvm/lib/Analysis/CMakeLists.txt
index 57ad437ef4f..c612221d994 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
+  LazyBranchProbabilityInfo.cpp
   LazyBlockFrequencyInfo.cpp
   LazyCallGraph.cpp
   LazyValueInfo.cpp
diff --git a/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp b/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp
index 7debfde87d2..596b6fc1afb 100644
--- a/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp
+++ b/llvm/lib/Analysis/LazyBlockFrequencyInfo.cpp
@@ -15,7 +15,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/LazyBlockFrequencyInfo.h"
-#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/LazyBranchProbabilityInfo.h"
 #include "llvm/Analysis/LoopInfo.h"
 
 using namespace llvm;
@@ -24,7 +24,7 @@ using namespace llvm;
 
 INITIALIZE_PASS_BEGIN(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
                       "Lazy Block Frequency Analysis", true, true)
-INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LazyBPIPass)
 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
 INITIALIZE_PASS_END(LazyBlockFrequencyInfoPass, DEBUG_TYPE,
                     "Lazy Block Frequency Analysis", true, true)
@@ -40,7 +40,7 @@ void LazyBlockFrequencyInfoPass::print(raw_ostream &OS, const Module *) const {
 }
 
 void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU);
   AU.addRequired<LoopInfoWrapperPass>();
   AU.setPreservesAll();
 }
@@ -48,21 +48,20 @@ void LazyBlockFrequencyInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
 void LazyBlockFrequencyInfoPass::releaseMemory() { LBFI.releaseMemory(); }
 
 bool LazyBlockFrequencyInfoPass::runOnFunction(Function &F) {
-  BranchProbabilityInfo &BPI =
-      getAnalysis<BranchProbabilityInfoWrapperPass>().getBPI();
+  auto &BPIPass = getAnalysis<LazyBranchProbabilityInfoPass>();
   LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-  LBFI.setAnalysis(&F, &BPI, &LI);
+  LBFI.setAnalysis(&F, &BPIPass, &LI);
   return false;
 }
 
 void LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AnalysisUsage &AU) {
-  AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AU);
   AU.addRequired<LazyBlockFrequencyInfoPass>();
   AU.addRequired<LoopInfoWrapperPass>();
 }
 
 void llvm::initializeLazyBFIPassPass(PassRegistry &Registry) {
-  INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass);
+  initializeLazyBPIPassPass(Registry);
   INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass);
   INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
 }
diff --git a/llvm/lib/Analysis/LazyBranchProbabilityInfo.cpp b/llvm/lib/Analysis/LazyBranchProbabilityInfo.cpp
new file mode 100644
index 00000000000..b51c6beb795
--- /dev/null
+++ b/llvm/lib/Analysis/LazyBranchProbabilityInfo.cpp
@@ -0,0 +1,63 @@
+//===- LazyBranchProbabilityInfo.cpp - Lazy Branch Probability 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 BranchProbabilityInfoWrapperPass.
+// The difference is that with this pass the branch probabilities are not
+// computed when the analysis pass is executed but rather when the BPI results
+// is explicitly requested by the analysis client.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/LazyBranchProbabilityInfo.h"
+#include "llvm/Analysis/LoopInfo.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "lazy-branch-prob"
+
+INITIALIZE_PASS_BEGIN(LazyBranchProbabilityInfoPass, DEBUG_TYPE,
+                      "Lazy Branch Probability Analysis", true, true)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
+INITIALIZE_PASS_END(LazyBranchProbabilityInfoPass, DEBUG_TYPE,
+                    "Lazy Branch Probability Analysis", true, true)
+
+char LazyBranchProbabilityInfoPass::ID = 0;
+
+LazyBranchProbabilityInfoPass::LazyBranchProbabilityInfoPass()
+    : FunctionPass(ID) {
+  initializeLazyBranchProbabilityInfoPassPass(*PassRegistry::getPassRegistry());
+}
+
+void LazyBranchProbabilityInfoPass::print(raw_ostream &OS,
+                                          const Module *) const {
+  LBPI->getCalculated().print(OS);
+}
+
+void LazyBranchProbabilityInfoPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.addRequired<LoopInfoWrapperPass>();
+  AU.setPreservesAll();
+}
+
+void LazyBranchProbabilityInfoPass::releaseMemory() { LBPI.reset(); }
+
+bool LazyBranchProbabilityInfoPass::runOnFunction(Function &F) {
+  LoopInfo &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+  LBPI = llvm::make_unique<LazyBranchProbabilityInfo>(&F, &LI);
+  return false;
+}
+
+void LazyBranchProbabilityInfoPass::getLazyBPIAnalysisUsage(AnalysisUsage &AU) {
+  AU.addRequired<LazyBranchProbabilityInfoPass>();
+  AU.addRequired<LoopInfoWrapperPass>();
+}
+
+void llvm::initializeLazyBPIPassPass(PassRegistry &Registry) {
+  INITIALIZE_PASS_DEPENDENCY(LazyBranchProbabilityInfoPass);
+  INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass);
+}