Teach the BranchProbabilityInfo pass to print its results, and use that

to bring it under direct test instead of merely indirectly testing it in
the BlockFrequencyInfo pass.

The next step is to start adding tests for the various heuristics
employed, and to start fixing those heuristics once they're under test.

llvm-svn: 142778

1 files changed, 20 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/BranchProbabilityInfo.cpp b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
index 4f15858aa34..9f175b070d3 100644
--- a/llvm/lib/Analysis/BranchProbabilityInfo.cpp
+++ b/llvm/lib/Analysis/BranchProbabilityInfo.cpp
@@ -12,11 +12,13 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Constants.h"
+#include "llvm/Function.h"
 #include "llvm/Instructions.h"
 #include "llvm/LLVMContext.h"
 #include "llvm/Metadata.h"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Support/CFG.h"
 #include "llvm/Support/Debug.h"
 
 using namespace llvm;
@@ -453,11 +455,26 @@ void BranchProbabilityInfo::getAnalysisUsage(AnalysisUsage &AU) const {
 }
 
 bool BranchProbabilityInfo::runOnFunction(Function &F) {
+  LastF = &F; // Store the last function we ran on for printing.
   LoopInfo &LI = getAnalysis<LoopInfo>();
   BranchProbabilityAnalysis BPA(this, &LI);
   return BPA.runOnFunction(F);
 }
 
+void BranchProbabilityInfo::print(raw_ostream &OS, const Module *) const {
+  OS << "---- Branch Probabilities ----\n";
+  // We print the probabilities from the last function the analysis ran over,
+  // or the function it is currently running over.
+  assert(LastF && "Cannot print prior to running over a function");
+  for (Function::const_iterator BI = LastF->begin(), BE = LastF->end();
+       BI != BE; ++BI) {
+    for (succ_const_iterator SI = succ_begin(BI), SE = succ_end(BI);
+         SI != SE; ++SI) {
+      printEdgeProbability(OS << "  ", BI, *SI);
+    }
+  }
+}
+
 uint32_t BranchProbabilityInfo::getSumForBlock(const BasicBlock *BB) const {
   uint32_t Sum = 0;
 
@@ -537,8 +554,9 @@ getEdgeProbability(const BasicBlock *Src, const BasicBlock *Dst) const {
 }
 
 raw_ostream &
-BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS, BasicBlock *Src,
-                                            BasicBlock *Dst) const {
+BranchProbabilityInfo::printEdgeProbability(raw_ostream &OS,
+                                            const BasicBlock *Src,
+                                            const BasicBlock *Dst) const {
 
   const BranchProbability Prob = getEdgeProbability(Src, Dst);
   OS << "edge " << Src->getNameStr() << " -> " << Dst->getNameStr()