Reverts wrong modification to MachineBlockPlacement & BranchFolding; uses a new strat...

[oota-llvm.git] / lib / CodeGen / MachineBlockPlacement.cpp

diff --git a/lib/CodeGen/MachineBlockPlacement.cpp b/lib/CodeGen/MachineBlockPlacement.cpp
index ddddd483e8013ea9bcdfdf4ec056423005057825..f5e3056450116514c2960b7c7794a248257bef1b 100644 (file)
--- a/lib/CodeGen/MachineBlockPlacement.cpp
+++ b/lib/CodeGen/MachineBlockPlacement.cpp
@@ -62,6 +62,11 @@ static cl::opt<unsigned> AlignAllBlock("align-all-blocks",
                                                 "blocks in the function."),
                                        cl::init(0), cl::Hidden);
 
+static cl::opt<unsigned>
+    AlignAllLoops("align-all-loops",
+                  cl::desc("Force the alignment of all loops in the function."),
+                  cl::init(0), cl::Hidden);
+
 // FIXME: Find a good default for this flag and remove the flag.
 static cl::opt<unsigned> ExitBlockBias(
     "block-placement-exit-block-bias",
@@ -423,9 +428,13 @@ MachineBlockPlacement::selectBestSuccessor(MachineBasicBlock *BB,
 
   DEBUG(dbgs() << "Attempting merge from: " << getBlockName(BB) << "\n");
   for (MachineBasicBlock *Succ : Successors) {
-    BranchProbability SuccProb(
-        MBPI->getEdgeProbability(BB, Succ).getNumerator(),
-        AdjustedSumProb.getNumerator());
+    BranchProbability SuccProb;
+    uint32_t SuccProbN = MBPI->getEdgeProbability(BB, Succ).getNumerator();
+    uint32_t SuccProbD = AdjustedSumProb.getNumerator();
+    if (SuccProbN >= SuccProbD)
+      SuccProb = BranchProbability::getOne();
+    else
+      SuccProb = BranchProbability(SuccProbN, SuccProbD);
 
     // If we outline optional branches, look whether Succ is unavoidable, i.e.
     // dominates all terminators of the MachineFunction. If it does, other
@@ -1325,6 +1334,11 @@ void MachineBlockPlacement::buildCFGChains(MachineFunction &F) {
     if (!L)
       continue;
 
+    if (AlignAllLoops) {
+      ChainBB->setAlignment(AlignAllLoops);
+      continue;
+    }
+
     unsigned Align = TLI->getPrefLoopAlignment(L);
     if (!Align)
       continue; // Don't care about loop alignment.