Revert r216066, "Optimize ZERO_EXTEND and SIGN_EXTEND in both SelectionDAG Builder...

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

diff --git a/lib/CodeGen/RegAllocGreedy.cpp b/lib/CodeGen/RegAllocGreedy.cpp
index c4f98007da96f84da15a064b65ee6b66ad75eb0b..a3a8760c54e4b7a0b48cd718e759b290d2ca0685 100644 (file)
--- a/lib/CodeGen/RegAllocGreedy.cpp
+++ b/lib/CodeGen/RegAllocGreedy.cpp
@@ -12,7 +12,6 @@
 //
 //===----------------------------------------------------------------------===//
 
-#define DEBUG_TYPE "regalloc"
 #include "llvm/CodeGen/Passes.h"
 #include "AllocationOrder.h"
 #include "InterferenceCache.h"
@@ -45,10 +44,13 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
 #include <queue>
 
 using namespace llvm;
 
+#define DEBUG_TYPE "regalloc"
+
 STATISTIC(NumGlobalSplits, "Number of split global live ranges");
 STATISTIC(NumLocalSplits,  "Number of split local live ranges");
 STATISTIC(NumEvicted,      "Number of interferences evicted");
@@ -78,6 +80,12 @@ ExhaustiveSearch("exhaustive-register-search", cl::NotHidden,
                  cl::desc("Exhaustive Search for registers bypassing the depth "
                           "and interference cutoffs of last chance recoloring"));
 
+static cl::opt<bool> EnableLocalReassignment(
+    "enable-local-reassign", cl::Hidden,
+    cl::desc("Local reassignment can yield better allocation decisions, but "
+             "may be compile time intensive"),
+    cl::init(false));
+
 // FIXME: Find a good default for this flag and remove the flag.
 static cl::opt<unsigned>
 CSRFirstTimeCost("regalloc-csr-first-time-cost",
@@ -284,6 +292,10 @@ class RAGreedy : public MachineFunctionPass,
   /// Callee-save register cost, calculated once per machine function.
   BlockFrequency CSRCost;
 
+  /// Run or not the local reassignment heuristic. This information is
+  /// obtained from the TargetSubtargetInfo.
+  bool EnableLocalReassign;
+
 public:
   RAGreedy();
 
@@ -474,7 +486,7 @@ void RAGreedy::LRE_DidCloneVirtReg(unsigned New, unsigned Old) {
 }
 
 void RAGreedy::releaseMemory() {
-  SpillerInstance.reset(0);
+  SpillerInstance.reset();
   ExtraRegInfo.clear();
   GlobalCand.clear();
 }
@@ -541,7 +553,7 @@ LiveInterval *RAGreedy::dequeue() { return dequeue(Queue); }
 
 LiveInterval *RAGreedy::dequeue(PQueue &CurQueue) {
   if (CurQueue.empty())
-    return 0;
+    return nullptr;
   LiveInterval *LI = &LIS->getInterval(~CurQueue.top().second);
   CurQueue.pop();
   return LI;
@@ -730,7 +742,7 @@ bool RAGreedy::canEvictInterference(LiveInterval &VirtReg, unsigned PhysReg,
       // Evicting another local live range in this case could lead to suboptimal
       // coloring.
       if (!MaxCost.isMax() && IsLocal && LIS->intervalIsInOneMBB(*Intf) &&
-          !canReassign(*Intf, PhysReg)) {
+          (!EnableLocalReassign || !canReassign(*Intf, PhysReg))) {
         return false;
       }
     }
@@ -2307,9 +2319,14 @@ bool RAGreedy::runOnMachineFunction(MachineFunction &mf) {
                << "********** Function: " << mf.getName() << '\n');
 
   MF = &mf;
-  TRI = MF->getTarget().getRegisterInfo();
-  TII = MF->getTarget().getInstrInfo();
+  const TargetMachine &TM = MF->getTarget();
+  TRI = TM.getSubtargetImpl()->getRegisterInfo();
+  TII = TM.getSubtargetImpl()->getInstrInfo();
   RCI.runOnMachineFunction(mf);
+
+  EnableLocalReassign = EnableLocalReassignment ||
+    TM.getSubtargetImpl()->enableRALocalReassignment(TM.getOptLevel());
+
   if (VerifyEnabled)
     MF->verify(this, "Before greedy register allocator");