Vendor import of llvm trunk r302418:vendor/llvm/llvm-trunk-r302418

https://llvm.org/svn/llvm-project/llvm/trunk@302418

1 files changed, 70 insertions, 3 deletions

diff --git a/lib/CodeGen/MIRPrinter.cpp b/lib/CodeGen/MIRPrinter.cpp
index d017b21f0a59..6f6a67d81b0f 100644
--- a/lib/CodeGen/MIRPrinter.cpp
+++ b/lib/CodeGen/MIRPrinter.cpp
@@ -12,7 +12,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "MIRPrinter.h"
+#include "llvm/CodeGen/MIRPrinter.h"
+
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallBitVector.h"
 #include "llvm/CodeGen/GlobalISel/RegisterBank.h"
@@ -34,6 +35,7 @@
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Options.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetInstrInfo.h"
@@ -42,6 +44,9 @@
 
 using namespace llvm;
 
+static cl::opt<bool> SimplifyMIR("simplify-mir",
+    cl::desc("Leave out unnecessary information when printing MIR"));
+
 namespace {
 
 /// This structure describes how to print out stack object references.
@@ -105,6 +110,9 @@ class MIPrinter {
   const DenseMap<const uint32_t *, unsigned> &RegisterMaskIds;
   const DenseMap<int, FrameIndexOperand> &StackObjectOperandMapping;
 
+  bool canPredictBranchProbabilities(const MachineBasicBlock &MBB) const;
+  bool canPredictSuccessors(const MachineBasicBlock &MBB) const;
+
 public:
   MIPrinter(raw_ostream &OS, ModuleSlotTracker &MST,
             const DenseMap<const uint32_t *, unsigned> &RegisterMaskIds,
@@ -454,6 +462,63 @@ void MIRPrinter::initRegisterMaskIds(const MachineFunction &MF) {
     RegisterMaskIds.insert(std::make_pair(Mask, I++));
 }
 
+void llvm::guessSuccessors(const MachineBasicBlock &MBB,
+                           SmallVectorImpl<MachineBasicBlock*> &Result,
+                           bool &IsFallthrough) {
+  SmallPtrSet<MachineBasicBlock*,8> Seen;
+
+  for (const MachineInstr &MI : MBB) {
+    if (MI.isPHI())
+      continue;
+    for (const MachineOperand &MO : MI.operands()) {
+      if (!MO.isMBB())
+        continue;
+      MachineBasicBlock *Succ = MO.getMBB();
+      auto RP = Seen.insert(Succ);
+      if (RP.second)
+        Result.push_back(Succ);
+    }
+  }
+  MachineBasicBlock::const_iterator I = MBB.getLastNonDebugInstr();
+  IsFallthrough = I == MBB.end() || !I->isBarrier();
+}
+
+bool
+MIPrinter::canPredictBranchProbabilities(const MachineBasicBlock &MBB) const {
+  if (MBB.succ_size() <= 1)
+    return true;
+  if (!MBB.hasSuccessorProbabilities())
+    return true;
+
+  SmallVector<BranchProbability,8> Normalized(MBB.Probs.begin(),
+                                              MBB.Probs.end());
+  BranchProbability::normalizeProbabilities(Normalized.begin(),
+                                            Normalized.end());
+  SmallVector<BranchProbability,8> Equal(Normalized.size());
+  BranchProbability::normalizeProbabilities(Equal.begin(), Equal.end());
+
+  return std::equal(Normalized.begin(), Normalized.end(), Equal.begin());
+}
+
+bool MIPrinter::canPredictSuccessors(const MachineBasicBlock &MBB) const {
+  SmallVector<MachineBasicBlock*,8> GuessedSuccs;
+  bool GuessedFallthrough;
+  guessSuccessors(MBB, GuessedSuccs, GuessedFallthrough);
+  if (GuessedFallthrough) {
+    const MachineFunction &MF = *MBB.getParent();
+    MachineFunction::const_iterator NextI = std::next(MBB.getIterator());
+    if (NextI != MF.end()) {
+      MachineBasicBlock *Next = const_cast<MachineBasicBlock*>(&*NextI);
+      if (!is_contained(GuessedSuccs, Next))
+        GuessedSuccs.push_back(Next);
+    }
+  }
+  if (GuessedSuccs.size() != MBB.succ_size())
+    return false;
+  return std::equal(MBB.succ_begin(), MBB.succ_end(), GuessedSuccs.begin());
+}
+
+
 void MIPrinter::print(const MachineBasicBlock &MBB) {
   assert(MBB.getNumber() >= 0 && "Invalid MBB number");
   OS << "bb." << MBB.getNumber();
@@ -492,13 +557,15 @@ void MIPrinter::print(const MachineBasicBlock &MBB) {
 
   bool HasLineAttributes = false;
   // Print the successors
-  if (!MBB.succ_empty()) {
+  bool canPredictProbs = canPredictBranchProbabilities(MBB);
+  if (!MBB.succ_empty() && (!SimplifyMIR || !canPredictProbs ||
+                            !canPredictSuccessors(MBB))) {
     OS.indent(2) << "successors: ";
     for (auto I = MBB.succ_begin(), E = MBB.succ_end(); I != E; ++I) {
       if (I != MBB.succ_begin())
         OS << ", ";
       printMBBReference(**I);
-      if (MBB.hasSuccessorProbabilities())
+      if (!SimplifyMIR || !canPredictProbs)
         OS << '('
            << format("0x%08" PRIx32, MBB.getSuccProbability(I).getNumerator())
            << ')';