Reapply a fixed version of r133285.

[oota-llvm.git] / lib / Transforms / InstCombine / InstCombineVectorOps.cpp

diff --git a/lib/Transforms/InstCombine/InstCombineVectorOps.cpp b/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
index 4aa1328f134511dbdbd0357fcfba7848a6d38124..ad6a8d054ee753f1714855a0e8a6995b0e45b401 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
+++ b/lib/Transforms/InstCombine/InstCombineVectorOps.cpp
@@ -230,8 +230,16 @@ Instruction *InstCombiner::visitExtractElementInst(ExtractElementInst &EI) {
                                           ConstantInt::get(Int32Ty,
                                                            SrcIdx, false));
       }
+    } else if (CastInst *CI = dyn_cast<CastInst>(I)) {
+      // Canonicalize extractelement(cast) -> cast(extractelement)
+      // bitcasts can change the number of vector elements and they cost nothing
+      if (CI->hasOneUse() && EI.hasOneUse() &&
+          (CI->getOpcode() != Instruction::BitCast)) {
+        Value *EE = Builder->CreateExtractElement(CI->getOperand(0),
+                                                  EI.getIndexOperand());
+        return CastInst::Create(CI->getOpcode(), EE, EI.getType());
+      }
     }
-    // FIXME: Canonicalize extractelement(bitcast) -> bitcast(extractelement)
   }
   return 0;
 }
@@ -426,8 +434,11 @@ Instruction *InstCombiner::visitInsertElementInst(InsertElementInst &IE) {
   unsigned VWidth = cast<VectorType>(VecOp->getType())->getNumElements();
   APInt UndefElts(VWidth, 0);
   APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
-  if (SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts))
+  if (Value *V = SimplifyDemandedVectorElts(&IE, AllOnesEltMask, UndefElts)) {
+    if (V != &IE)
+      return ReplaceInstUsesWith(IE, V);
     return &IE;
+  }
 
   return 0;
 }
@@ -451,7 +462,9 @@ Instruction *InstCombiner::visitShuffleVectorInst(ShuffleVectorInst &SVI) {
 
   APInt UndefElts(VWidth, 0);
   APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
-  if (SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
+  if (Value *V = SimplifyDemandedVectorElts(&SVI, AllOnesEltMask, UndefElts)) {
+    if (V != &SVI)
+      return ReplaceInstUsesWith(SVI, V);
     LHS = SVI.getOperand(0);
     RHS = SVI.getOperand(1);
     MadeChange = true;