Extract live range calculations from SplitKit.

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

diff --git a/lib/CodeGen/UnreachableBlockElim.cpp b/lib/CodeGen/UnreachableBlockElim.cpp
index ebf1129d55abd5f253e02944569bffdee6b99adc..52693f03e82822e6bb9e87b98ef324b3c717ed78 100644 (file)
--- a/lib/CodeGen/UnreachableBlockElim.cpp
+++ b/lib/CodeGen/UnreachableBlockElim.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Function.h"
 #include "llvm/Pass.h"
 #include "llvm/Type.h"
+#include "llvm/Analysis/Dominators.h"
 #include "llvm/Analysis/ProfileInfo.h"
 #include "llvm/CodeGen/MachineDominators.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
@@ -43,16 +44,19 @@ namespace {
     virtual bool runOnFunction(Function &F);
   public:
     static char ID; // Pass identification, replacement for typeid
-    UnreachableBlockElim() : FunctionPass(ID) {}
+    UnreachableBlockElim() : FunctionPass(ID) {
+      initializeUnreachableBlockElimPass(*PassRegistry::getPassRegistry());
+    }
 
     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addPreserved<DominatorTree>();
       AU.addPreserved<ProfileInfo>();
     }
   };
 }
 char UnreachableBlockElim::ID = 0;
 INITIALIZE_PASS(UnreachableBlockElim, "unreachableblockelim",
-                "Remove unreachable blocks from the CFG", false, false);
+                "Remove unreachable blocks from the CFG", false, false)
 
 FunctionPass *llvm::createUnreachableBlockEliminationPass() {
   return new UnreachableBlockElim();
@@ -106,7 +110,7 @@ namespace {
 char UnreachableMachineBlockElim::ID = 0;
 
 INITIALIZE_PASS(UnreachableMachineBlockElim, "unreachable-mbb-elimination",
-  "Remove unreachable machine basic blocks", false, false);
+  "Remove unreachable machine basic blocks", false, false)
 
 char &llvm::UnreachableMachineBlockElimID = UnreachableMachineBlockElim::ID;
 
@@ -192,8 +196,11 @@ bool UnreachableMachineBlockElim::runOnMachineFunction(MachineFunction &F) {
         temp->eraseFromParent();
         ModifiedPHI = true;
 
-        if (Input != Output)
-          F.getRegInfo().replaceRegWith(Output, Input);
+        if (Input != Output) {
+          MachineRegisterInfo &MRI = F.getRegInfo();
+          MRI.constrainRegClass(Input, MRI.getRegClass(Output));
+          MRI.replaceRegWith(Output, Input);
+        }
 
         continue;
       }