X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineBranchProbabilityInfo.cpp;h=6fbc2be70486ad3ff2059ebae14fa9aa1edd56f2;hb=33966cf988cb9db5c8f839bf8b8509f12db4a529;hp=e3cfa9ea5afcbee458358a2ed91de585d9e14034;hpb=c4e15628255b24cb17138404abe3d94bde811e25;p=oota-llvm.git

diff --git a/lib/CodeGen/MachineBranchProbabilityInfo.cpp b/lib/CodeGen/MachineBranchProbabilityInfo.cpp
index e3cfa9ea5af..6fbc2be7048 100644
--- a/lib/CodeGen/MachineBranchProbabilityInfo.cpp
+++ b/lib/CodeGen/MachineBranchProbabilityInfo.cpp
@@ -11,9 +11,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Instructions.h"
 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
 #include "llvm/CodeGen/MachineBasicBlock.h"
+#include "llvm/IR/Instructions.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -26,8 +26,10 @@ INITIALIZE_PASS_END(MachineBranchProbabilityInfo, "machine-branch-prob",
 
 char MachineBranchProbabilityInfo::ID = 0;
 
+void MachineBranchProbabilityInfo::anchor() { }
+
 uint32_t MachineBranchProbabilityInfo::
-getSumForBlock(MachineBasicBlock *MBB, uint32_t &Scale) const {
+getSumForBlock(const MachineBasicBlock *MBB, uint32_t &Scale) const {
   // First we compute the sum with 64-bits of precision, ensuring that cannot
   // overflow by bounding the number of weights considered. Hopefully no one
   // actually needs 2^32 successors.
@@ -36,7 +38,7 @@ getSumForBlock(MachineBasicBlock *MBB, uint32_t &Scale) const {
   Scale = 1;
   for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
        E = MBB->succ_end(); I != E; ++I) {
-    uint32_t Weight = getEdgeWeight(MBB, *I);
+    uint32_t Weight = getEdgeWeight(MBB, I);
     Sum += Weight;
   }
 
@@ -51,24 +53,33 @@ getSumForBlock(MachineBasicBlock *MBB, uint32_t &Scale) const {
   Sum = 0;
   for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
        E = MBB->succ_end(); I != E; ++I) {
-    uint32_t Weight = getEdgeWeight(MBB, *I);
+    uint32_t Weight = getEdgeWeight(MBB, I);
     Sum += Weight / Scale;
   }
   assert(Sum <= UINT32_MAX);
   return Sum;
 }
 
-uint32_t
-MachineBranchProbabilityInfo::getEdgeWeight(MachineBasicBlock *Src,
-                                            MachineBasicBlock *Dst) const {
+uint32_t MachineBranchProbabilityInfo::
+getEdgeWeight(const MachineBasicBlock *Src,
+              MachineBasicBlock::const_succ_iterator Dst) const {
   uint32_t Weight = Src->getSuccWeight(Dst);
   if (!Weight)
     return DEFAULT_WEIGHT;
   return Weight;
 }
 
-bool MachineBranchProbabilityInfo::isEdgeHot(MachineBasicBlock *Src,
-                                             MachineBasicBlock *Dst) const {
+uint32_t MachineBranchProbabilityInfo::
+getEdgeWeight(const MachineBasicBlock *Src,
+              const MachineBasicBlock *Dst) const {
+  // This is a linear search. Try to use the const_succ_iterator version when
+  // possible.
+  return getEdgeWeight(Src, std::find(Src->succ_begin(), Src->succ_end(), Dst));
+}
+
+bool
+MachineBranchProbabilityInfo::isEdgeHot(const MachineBasicBlock *Src,
+                                        const MachineBasicBlock *Dst) const {
   // Hot probability is at least 4/5 = 80%
   // FIXME: Compare against a static "hot" BranchProbability.
   return getEdgeProbability(Src, Dst) > BranchProbability(4, 5);
@@ -77,10 +88,10 @@ bool MachineBranchProbabilityInfo::isEdgeHot(MachineBasicBlock *Src,
 MachineBasicBlock *
 MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const {
   uint32_t MaxWeight = 0;
-  MachineBasicBlock *MaxSucc = 0;
+  MachineBasicBlock *MaxSucc = nullptr;
   for (MachineBasicBlock::const_succ_iterator I = MBB->succ_begin(),
        E = MBB->succ_end(); I != E; ++I) {
-    uint32_t Weight = getEdgeWeight(MBB, *I);
+    uint32_t Weight = getEdgeWeight(MBB, I);
     if (Weight > MaxWeight) {
       MaxWeight = Weight;
       MaxSucc = *I;
@@ -90,12 +101,11 @@ MachineBranchProbabilityInfo::getHotSucc(MachineBasicBlock *MBB) const {
   if (getEdgeProbability(MBB, MaxSucc) >= BranchProbability(4, 5))
     return MaxSucc;
 
-  return 0;
+  return nullptr;
 }
 
-BranchProbability
-MachineBranchProbabilityInfo::getEdgeProbability(MachineBasicBlock *Src,
-                                                 MachineBasicBlock *Dst) const {
+BranchProbability MachineBranchProbabilityInfo::getEdgeProbability(
+    const MachineBasicBlock *Src, const MachineBasicBlock *Dst) const {
   uint32_t Scale = 1;
   uint32_t D = getSumForBlock(Src, Scale);
   uint32_t N = getEdgeWeight(Src, Dst) / Scale;
@@ -103,13 +113,13 @@ MachineBranchProbabilityInfo::getEdgeProbability(MachineBasicBlock *Src,
   return BranchProbability(N, D);
 }
 
-raw_ostream &MachineBranchProbabilityInfo::
-printEdgeProbability(raw_ostream &OS, MachineBasicBlock *Src,
-                     MachineBasicBlock *Dst) const {
+raw_ostream &MachineBranchProbabilityInfo::printEdgeProbability(
+    raw_ostream &OS, const MachineBasicBlock *Src,
+    const MachineBasicBlock *Dst) const {
 
   const BranchProbability Prob = getEdgeProbability(Src, Dst);
   OS << "edge MBB#" << Src->getNumber() << " -> MBB#" << Dst->getNumber()
-     << " probability is "  << Prob 
+     << " probability is " << Prob
      << (isEdgeHot(Src, Dst) ? " [HOT edge]\n" : "\n");
 
   return OS;