InstCombine: allow unmasked icmps to be combined with logical ops

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

diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 2defe631ae7a734a7c7ed885f774809ee6a4f3e3..7581dbe0f0806b9451291f396c986f795bf4878c 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -662,7 +662,7 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
                                 ConstantInt *FalseVal,
                                 InstCombiner::BuilderTy *Builder) {
   const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
-  if (!IC || !IC->isEquality())
+  if (!IC || !IC->isEquality() || !SI.getType()->isIntegerTy())
     return 0;
 
   if (!match(IC->getOperand(1), m_Zero()))
@@ -670,8 +670,7 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
 
   ConstantInt *AndRHS;
   Value *LHS = IC->getOperand(0);
-  if (LHS->getType() != SI.getType() ||
-      !match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
+  if (!match(LHS, m_And(m_Value(), m_ConstantInt(AndRHS))))
     return 0;
 
   // If both select arms are non-zero see if we have a select of the form
@@ -705,7 +704,13 @@ static Value *foldSelectICmpAnd(const SelectInst &SI, ConstantInt *TrueVal,
   unsigned ValZeros = ValC->getValue().logBase2();
   unsigned AndZeros = AndRHS->getValue().logBase2();
 
-  Value *V = LHS;
+  // If types don't match we can still convert the select by introducing a zext
+  // or a trunc of the 'and'. The trunc case requires that all of the truncated
+  // bits are zero, we can figure that out by looking at the 'and' mask.
+  if (AndZeros >= ValC->getBitWidth())
+    return 0;
+
+  Value *V = Builder->CreateZExtOrTrunc(LHS, SI.getType());
   if (ValZeros > AndZeros)
     V = Builder->CreateShl(V, ValZeros - AndZeros);
   else if (ValZeros < AndZeros)
@@ -974,7 +979,7 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
     return &SI;
   }
 
-  if (VectorType *VecTy = dyn_cast<VectorType>(SI.getType())) {
+  if (VectorType* VecTy = dyn_cast<VectorType>(SI.getType())) {
     unsigned VWidth = VecTy->getNumElements();
     APInt UndefElts(VWidth, 0);
     APInt AllOnesEltMask(APInt::getAllOnesValue(VWidth));
@@ -984,24 +989,6 @@ Instruction *InstCombiner::visitSelectInst(SelectInst &SI) {
       return &SI;
     }
 
-    if (ConstantVector *CV = dyn_cast<ConstantVector>(CondVal)) {
-      // Form a shufflevector instruction.
-      SmallVector<Constant *, 8> Mask(VWidth);
-      Type *Int32Ty = Type::getInt32Ty(CV->getContext());
-      for (unsigned i = 0; i != VWidth; ++i) {
-        Constant *Elem = cast<Constant>(CV->getOperand(i));
-        if (ConstantInt *E = dyn_cast<ConstantInt>(Elem))
-          Mask[i] = ConstantInt::get(Int32Ty, i + (E->isZero() ? VWidth : 0));
-        else if (isa<UndefValue>(Elem))
-          Mask[i] = UndefValue::get(Int32Ty);
-        else
-          return 0;
-      }
-      Constant *MaskVal = ConstantVector::get(Mask);
-      Value *V = Builder->CreateShuffleVector(TrueVal, FalseVal, MaskVal);
-      return ReplaceInstUsesWith(SI, V);
-    }
-
     if (isa<ConstantAggregateZero>(CondVal)) {
       return ReplaceInstUsesWith(SI, FalseVal);
     }