Implement Constant::isAllOnesValue(). Fix ConstantFolding to use the new api.

llvm-svn: 138469

2 files changed, 28 insertions, 13 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 7a8c703040c..df79849c3cf 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -45,16 +45,12 @@ using namespace llvm;
 /// ConstantExpr if unfoldable.
 static Constant *FoldBitCast(Constant *C, Type *DestTy,
                              const TargetData &TD) {
-  
-  ConstantVector *CV = dyn_cast<ConstantVector>(C);
-  IntegerType *IntVTy = dyn_cast<IntegerType>(DestTy);
-  // When casting vectors to scalar integers, catch the
-  // obvious splat cases.
-  if (IntVTy && CV) {
-    if (CV->isNullValue()) return ConstantInt::getNullValue(IntVTy);
-    if (CV->isAllOnesValue()) return ConstantInt::getAllOnesValue(IntVTy);
-  }
-  
+  // Catch the obvious splat cases.
+  if (C->isNullValue() && !DestTy->isX86_MMXTy())
+    return Constant::getNullValue(DestTy);
+  if (C->isAllOnesValue() && !DestTy->isX86_MMXTy())
+    return Constant::getAllOnesValue(DestTy);
+
   // The code below only handles casts to vectors currently.
   VectorType *DestVTy = dyn_cast<VectorType>(DestTy);
   if (DestVTy == 0)
@@ -68,6 +64,7 @@ static Constant *FoldBitCast(Constant *C, Type *DestTy,
   }
   
   // If this is a bitcast from constant vector -> vector, fold it.
+  ConstantVector *CV = dyn_cast<ConstantVector>(C);
   if (CV == 0)
     return ConstantExpr::getBitCast(C, DestTy);
   
diff --git a/llvm/lib/VMCore/Constants.cpp b/llvm/lib/VMCore/Constants.cpp
index 2f22cda5ba4..ba309d9ca07 100644
--- a/llvm/lib/VMCore/Constants.cpp
+++ b/llvm/lib/VMCore/Constants.cpp
@@ -62,6 +62,21 @@ bool Constant::isNullValue() const {
   return isa<ConstantAggregateZero>(this) || isa<ConstantPointerNull>(this);
 }
 
+bool Constant::isAllOnesValue() const {
+  // Check for -1 integers
+  if (const ConstantInt *CI = dyn_cast<ConstantInt>(this))
+    return CI->isMinusOne();
+
+  // Check for FP which are bitcasted from -1 integers
+  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(this))
+    return CFP->getValueAPF().bitcastToAPInt().isAllOnesValue();
+
+  // Check for constant vectors
+  if (const ConstantVector *CV = dyn_cast<ConstantVector>(this))
+    return CV->isAllOnesValue();
+
+  return false;
+}
 // Constructor to create a '0' constant of arbitrary type...
 Constant *Constant::getNullValue(Type *Ty) {
   switch (Ty->getTypeID()) {
@@ -126,7 +141,7 @@ Constant *Constant::getAllOnesValue(Type *Ty) {
   SmallVector<Constant*, 16> Elts;
   VectorType *VTy = cast<VectorType>(Ty);
   Elts.resize(VTy->getNumElements(), getAllOnesValue(VTy->getElementType()));
-  assert(Elts[0] && "Not a vector integer type!");
+  assert(Elts[0] && "Invalid AllOnes value!");
   return cast<ConstantVector>(ConstantVector::get(Elts));
 }
 
@@ -1064,13 +1079,16 @@ bool ConstantVector::isAllOnesValue() const {
   // Check out first element.
   const Constant *Elt = getOperand(0);
   const ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
-  if (!CI || !CI->isAllOnesValue()) return false;
+  const ConstantFP *CF = dyn_cast<ConstantFP>(Elt);
+
   // Then make sure all remaining elements point to the same value.
   for (unsigned I = 1, E = getNumOperands(); I < E; ++I)
     if (getOperand(I) != Elt)
       return false;
   
-  return true;
+  // First value is all-ones.
+  return (CI && CI->isAllOnesValue()) || 
+         (CF && CF->isAllOnesValue());
 }
 
 /// getSplatValue - If this is a splat constant, where all of the