Auto-upgrade code for multiple-value return statements. This code

isn't actually called yet.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52435 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 30 insertions, 0 deletions

diff --git a/include/llvm/AutoUpgrade.h b/include/llvm/AutoUpgrade.h
index 3a97353ac9..023587790f 100644
--- a/include/llvm/AutoUpgrade.h
+++ b/include/llvm/AutoUpgrade.h
@@ -35,6 +35,12 @@ namespace llvm {
   /// so that it can update all calls to the old function.
   void UpgradeCallsToIntrinsic(Function* F);
 
+  /// This is an auto-upgrade hook for mutiple-value return statements.
+  /// This function auto-upgrades all such return statements in the given
+  /// function to use aggregate return values built with insertvalue
+  /// instructions.
+  void UpgradeMultipleReturnValues(Function *F);
+
 } // End llvm namespace
 
 #endif
diff --git a/lib/VMCore/AutoUpgrade.cpp b/lib/VMCore/AutoUpgrade.cpp
index 2f1e07c211..7b6369208c 100644
--- a/lib/VMCore/AutoUpgrade.cpp
+++ b/lib/VMCore/AutoUpgrade.cpp
@@ -391,3 +391,27 @@ void llvm::UpgradeCallsToIntrinsic(Function* F) {
   }
 }
 
+/// This is an auto-upgrade hook for mutiple-value return statements.
+/// This function auto-upgrades all such return statements in the given
+/// function to use aggregate return values built with insertvalue
+/// instructions.
+void llvm::UpgradeMultipleReturnValues(Function *CurrentFunction) {
+  for (Function::iterator I = CurrentFunction->begin(),
+       E = CurrentFunction->end(); I != E; ++I) {
+    BasicBlock *BB = I;
+    if (ReturnInst *RI = dyn_cast<ReturnInst>(BB->getTerminator())) {
+      unsigned NumVals = RI->getNumOperands();
+      if (NumVals > 1) {
+        std::vector<const Type *> Types(NumVals);
+        for (unsigned i = 0; i != NumVals; ++i)
+          Types[i] = RI->getOperand(i)->getType();
+        const Type *ReturnType = StructType::get(Types);
+        Value *RV = UndefValue::get(ReturnType);
+        for (unsigned i = 0; i != NumVals; ++i)
+          RV = InsertValueInst::Create(RV, RI->getOperand(i), i, "mrv", RI);
+        ReturnInst::Create(RV, RI);
+        RI->eraseFromParent();
+      }
+    }
+  }
+}