[llvm-commits] CVS: llvm/lib/Transforms/Scalar/InstructionCombining.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

InstructionCombining.cpp updated: 1.471 -> 1.472
---
Log message:

Add support for inserting undef into a vector.  This implements
Transforms/InstCombine/vec_insert_to_shuffle.ll


---
Diffs of the changes:  (+14 -3)

 InstructionCombining.cpp |   17 ++++++++++++++---
 1 files changed, 14 insertions(+), 3 deletions(-)


Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.471 llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.472
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.471	Thu Apr 20 10:41:37 2006
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp	Thu Apr 27 16:14:21 2006
@@ -6959,12 +6959,23 @@
     Value *ScalarOp = IEI->getOperand(1);
     Value *IdxOp    = IEI->getOperand(2);
     
-    if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)) {
-      if (isa<ConstantInt>(EI->getOperand(1)) && isa<ConstantInt>(IdxOp) &&
+    if (!isa<ConstantInt>(IdxOp))
+      return false;
+    unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getRawValue();
+    
+    if (isa<UndefValue>(ScalarOp)) {  // inserting undef into vector.
+      // Okay, we can handle this if the vector we are insertinting into is
+      // transitively ok.
+      if (CollectSingleShuffleElements(VecOp, LHS, RHS, Mask)) {
+        // If so, update the mask to reflect the inserted undef.
+        Mask[InsertedIdx] = UndefValue::get(Type::UIntTy);
+        return true;
+      }      
+    } else if (ExtractElementInst *EI = dyn_cast<ExtractElementInst>(ScalarOp)){
+      if (isa<ConstantInt>(EI->getOperand(1)) &&
           EI->getOperand(0)->getType() == V->getType()) {
         unsigned ExtractedIdx =
           cast<ConstantInt>(EI->getOperand(1))->getRawValue();
-        unsigned InsertedIdx = cast<ConstantInt>(IdxOp)->getRawValue();
         
         // This must be extracting from either LHS or RHS.
         if (EI->getOperand(0) == LHS || EI->getOperand(0) == RHS) {