Fix a bug that David Greene found in the DAGCombiner's logic

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

diff --git a/lib/CodeGen/MachineSink.cpp b/lib/CodeGen/MachineSink.cpp
index 97a4df5497fe5dcf7975f71ead3c14175f77fcbe..468bd01548c244dacfaa675c275d4116941cb90c 100644 (file)
--- a/lib/CodeGen/MachineSink.cpp
+++ b/lib/CodeGen/MachineSink.cpp
@@ -18,7 +18,6 @@
 #include "llvm/Target/TargetRegisterInfo.h"
 #include "llvm/Target/TargetInstrInfo.h"
 #include "llvm/Target/TargetMachine.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/Debug.h"
@@ -36,7 +35,7 @@ namespace {
 
   public:
     static char ID; // Pass identification
-    MachineSinking() : MachineFunctionPass((intptr_t)&ID) {}
+    MachineSinking() : MachineFunctionPass(&ID) {}
     
     virtual bool runOnMachineFunction(MachineFunction &MF);
     
@@ -50,10 +49,11 @@ namespace {
     bool SinkInstruction(MachineInstr *MI, bool &SawStore);
     bool AllUsesDominatedByBlock(unsigned Reg, MachineBasicBlock *MBB) const;
   };
-  
-  char MachineSinking::ID = 0;
-  RegisterPass<MachineSinking> X("machine-sink", "Machine code sinking");
 } // end anonymous namespace
+  
+char MachineSinking::ID = 0;
+static RegisterPass<MachineSinking>
+X("machine-sink", "Machine code sinking");
 
 FunctionPass *llvm::createMachineSinkingPass() { return new MachineSinking(); }
 
@@ -167,6 +167,10 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
     } else {
       // Virtual register uses are always safe to sink.
       if (MO.isUse()) continue;
+
+      // If it's not safe to move defs of the register class, then abort.
+      if (!TII->isSafeToMoveRegClassDefs(RegInfo->getRegClass(Reg)))
+        return false;
       
       // FIXME: This picks a successor to sink into based on having one
       // successor that dominates all the uses.  However, there are cases where
@@ -208,6 +212,11 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
   // If there are no outputs, it must have side-effects.
   if (SuccToSinkTo == 0)
     return false;
+
+  // It's not safe to sink instructions to EH landing pad. Control flow into
+  // landing pad is implicitly defined.
+  if (SuccToSinkTo->isLandingPad())
+    return false;
   
   DEBUG(cerr << "Sink instr " << *MI);
   DEBUG(cerr << "to block " << *SuccToSinkTo);