Turn on FGETSIGN for x86. Followup to 132388. rdar://problem/5660695

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

diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp
index 0770a5f4d46dd2265dfb3e0d19891c99d0e25f8b..719cd264f684ddca232004826ff86161dc48d24e 100644 (file)
--- a/lib/CodeGen/BranchFolding.cpp
+++ b/lib/CodeGen/BranchFolding.cpp
@@ -1056,6 +1056,22 @@ ReoptimizeBlock:
         !MBB->hasAddressTaken() && !MBB->isLandingPad()) {
       DEBUG(dbgs() << "\nMerging into block: " << PrevBB
                    << "From MBB: " << *MBB);
+      // Remove redundant DBG_VALUEs first.
+      if (PrevBB.begin() != PrevBB.end()) {
+        MachineBasicBlock::iterator PrevBBIter = PrevBB.end();
+        --PrevBBIter;
+        MachineBasicBlock::iterator MBBIter = MBB->begin();
+        // Check if DBG_VALUE at the end of PrevBB is identical to the 
+        // DBG_VALUE at the beginning of MBB.
+        while (PrevBBIter != PrevBB.begin() && MBBIter != MBB->end()
+               && PrevBBIter->isDebugValue() && MBBIter->isDebugValue()) {
+          if (!MBBIter->isIdenticalTo(PrevBBIter))
+            break;
+          MachineInstr *DuplicateDbg = MBBIter;
+          ++MBBIter; -- PrevBBIter;
+          DuplicateDbg->eraseFromParent();
+        }
+      }
       PrevBB.splice(PrevBB.end(), MBB, MBB->begin(), MBB->end());
       PrevBB.removeSuccessor(PrevBB.succ_begin());;
       assert(PrevBB.succ_empty());
@@ -1351,8 +1367,6 @@ ReoptimizeBlock:
 
 /// HoistCommonCode - Hoist common instruction sequences at the start of basic
 /// blocks to their common predecessor.
-/// NOTE: This optimization does not update live-in information so it must be
-/// run after all passes that require correct liveness information.
 bool BranchFolder::HoistCommonCode(MachineFunction &MF) {
   bool MadeChange = false;
   for (MachineFunction::iterator I = MF.begin(), E = MF.end(); I != E; ) {
@@ -1468,10 +1482,10 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB,
         Uses.erase(Reg);
         for (const unsigned *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
           Uses.erase(*SR); // Use getSubRegisters to be conservative
-        Defs.insert(Reg);
-        for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
-          Defs.insert(*AS);
       }
+      Defs.insert(Reg);
+      for (const unsigned *AS = TRI->getAliasSet(Reg); *AS; ++AS)
+        Defs.insert(*AS);
     }
   }
 
@@ -1507,7 +1521,8 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
     return false;
 
   bool HasDups = false;
-  SmallSet<unsigned, 4> LocalDefs;
+  SmallVector<unsigned, 4> LocalDefs;
+  SmallSet<unsigned, 4> LocalDefsSet;
   MachineBasicBlock::iterator TIB = TBB->begin();
   MachineBasicBlock::iterator FIB = FBB->begin();
   MachineBasicBlock::iterator TIE = TBB->end();
@@ -1564,11 +1579,7 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
           IsSafe = false;
           break;
         }
-
-        LocalDefs.insert(Reg);
-        for (const unsigned *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
-          LocalDefs.insert(*SR);
-      } else if (!LocalDefs.count(Reg)) {
+      } else if (!LocalDefsSet.count(Reg)) {
         if (Defs.count(Reg)) {
           // Use is defined by the instruction at the point of insertion.
           IsSafe = false;
@@ -1583,6 +1594,28 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
     if (!TIB->isSafeToMove(TII, 0, DontMoveAcrossStore))
       break;
 
+    // Track local defs so we can update liveins.
+    for (unsigned i = 0, e = TIB->getNumOperands(); i != e; ++i) {
+      MachineOperand &MO = TIB->getOperand(i);
+      if (!MO.isReg())
+        continue;
+      unsigned Reg = MO.getReg();
+      if (!Reg)
+        continue;
+      if (MO.isDef()) {
+        if (!MO.isDead()) {
+          LocalDefs.push_back(Reg);
+          LocalDefsSet.insert(Reg);
+          for (const unsigned *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
+            LocalDefsSet.insert(*SR);
+        }
+      } else if (MO.isKill() && LocalDefsSet.count(Reg)) {
+        LocalDefsSet.erase(Reg);
+        for (const unsigned *SR = TRI->getSubRegisters(Reg); *SR; ++SR)
+          LocalDefsSet.erase(*SR);
+      }
+    }
+
     HasDups = true;;
     ++TIB;
     ++FIB;
@@ -1593,6 +1626,16 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
 
   MBB->splice(Loc, TBB, TBB->begin(), TIB);
   FBB->erase(FBB->begin(), FIB);
+
+  // Update livein's.
+  for (unsigned i = 0, e = LocalDefs.size(); i != e; ++i) {
+    unsigned Def = LocalDefs[i];
+    if (LocalDefsSet.count(Def)) {
+      TBB->addLiveIn(Def);
+      FBB->addLiveIn(Def);
+    }
+  }
+
   ++NumHoist;
   return true;
 }