Reapply "blockfreq: Rewrite BlockFrequencyInfoImpl"

This reverts commit r206677, reapplying my BlockFrequencyInfo rewrite.

I've done a careful audit, added some asserts, and fixed a couple of
bugs (unfortunately, they were in unlikely code paths).  There's a small
chance that this will appease the failing bots [1][2].  (If so, great!)

If not, I have a follow-up commit ready that will temporarily add
-debug-only=block-freq to the two failing tests, allowing me to compare
the code path between what the failing bots and what my machines (and
the rest of the bots) are doing.  Once I've triggered those builds, I'll
revert both commits so the bots go green again.

[1]: http://bb.pgr.jp/builders/ninja-x64-msvc-RA-centos6/builds/1816
[2]: http://llvm-amd64.freebsd.your.org/b/builders/clang-i386-freebsd/builds/18445

<rdar://problem/14292693>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206704 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 3 deletions

diff --git a/lib/CodeGen/MachineBlockFrequencyInfo.cpp b/lib/CodeGen/MachineBlockFrequencyInfo.cpp
index 70efa307d5..d3ac0c0437 100644
--- a/lib/CodeGen/MachineBlockFrequencyInfo.cpp
+++ b/lib/CodeGen/MachineBlockFrequencyInfo.cpp
@@ -11,9 +11,12 @@
 //
 //===----------------------------------------------------------------------===//
 
+#define DEBUG_TYPE "block-freq"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/Analysis/BlockFrequencyInfoImpl.h"
 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineLoopInfo.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Support/CommandLine.h"
@@ -112,6 +115,7 @@ struct DOTGraphTraits<MachineBlockFrequencyInfo*> :
 INITIALIZE_PASS_BEGIN(MachineBlockFrequencyInfo, "machine-block-freq",
                       "Machine Block Frequency Analysis", true, true)
 INITIALIZE_PASS_DEPENDENCY(MachineBranchProbabilityInfo)
+INITIALIZE_PASS_DEPENDENCY(MachineLoopInfo)
 INITIALIZE_PASS_END(MachineBlockFrequencyInfo, "machine-block-freq",
                     "Machine Block Frequency Analysis", true, true)
 
@@ -127,16 +131,18 @@ MachineBlockFrequencyInfo::~MachineBlockFrequencyInfo() {}
 
 void MachineBlockFrequencyInfo::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<MachineBranchProbabilityInfo>();
+  AU.addRequired<MachineLoopInfo>();
   AU.setPreservesAll();
   MachineFunctionPass::getAnalysisUsage(AU);
 }
 
 bool MachineBlockFrequencyInfo::runOnMachineFunction(MachineFunction &F) {
   MachineBranchProbabilityInfo &MBPI =
-    getAnalysis<MachineBranchProbabilityInfo>();
+      getAnalysis<MachineBranchProbabilityInfo>();
+  MachineLoopInfo &MLI = getAnalysis<MachineLoopInfo>();
   if (!MBFI)
     MBFI.reset(new ImplType);
-  MBFI->doFunction(&F, &MBPI);
+  MBFI->doFunction(&F, &MBPI, &MLI);
 #ifndef NDEBUG
   if (ViewMachineBlockFreqPropagationDAG != GVDT_None) {
     view();
@@ -166,7 +172,7 @@ getBlockFreq(const MachineBasicBlock *MBB) const {
 }
 
 const MachineFunction *MachineBlockFrequencyInfo::getFunction() const {
-  return MBFI ? MBFI->Fn : nullptr;
+  return MBFI ? MBFI->getFunction() : nullptr;
 }
 
 raw_ostream &