Consolidate existing utilities for interpreting vector predicate maskes [NFC]

llvm-svn: 359163

1 files changed, 46 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/VectorUtils.cpp b/llvm/lib/Analysis/VectorUtils.cpp
index ef70e14da7f..f1a05ae5055 100644
--- a/llvm/lib/Analysis/VectorUtils.cpp
+++ b/llvm/lib/Analysis/VectorUtils.cpp
@@ -715,6 +715,52 @@ Value *llvm::concatenateVectors(IRBuilder<> &Builder, ArrayRef<Value *> Vecs) {
   return ResList[0];
 }
 
+bool llvm::maskIsAllZeroOrUndef(Value *Mask) {
+  auto *ConstMask = dyn_cast<Constant>(Mask);
+  if (!ConstMask)
+    return false;
+  if (ConstMask->isNullValue() || isa<UndefValue>(ConstMask))
+    return true;
+  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
+       ++I) {
+    if (auto *MaskElt = ConstMask->getAggregateElement(I))
+      if (MaskElt->isNullValue() || isa<UndefValue>(MaskElt))
+        continue;
+    return false;
+  }
+  return true;
+}
+
+
+bool llvm::maskIsAllOneOrUndef(Value *Mask) {
+  auto *ConstMask = dyn_cast<Constant>(Mask);
+  if (!ConstMask)
+    return false;
+  if (ConstMask->isAllOnesValue() || isa<UndefValue>(ConstMask))
+    return true;
+  for (unsigned I = 0, E = ConstMask->getType()->getVectorNumElements(); I != E;
+       ++I) {
+    if (auto *MaskElt = ConstMask->getAggregateElement(I))
+      if (MaskElt->isAllOnesValue() || isa<UndefValue>(MaskElt))
+        continue;
+    return false;
+  }
+  return true;
+}
+
+/// TODO: This is a lot like known bits, but for
+/// vectors.  Is there something we can common this with?
+APInt llvm::possiblyDemandedEltsInMask(Value *Mask) {
+
+  const unsigned VWidth = cast<VectorType>(Mask->getType())->getNumElements();
+  APInt DemandedElts = APInt::getAllOnesValue(VWidth);
+  if (auto *CV = dyn_cast<ConstantVector>(Mask))
+    for (unsigned i = 0; i < VWidth; i++)
+      if (CV->getAggregateElement(i)->isNullValue())
+        DemandedElts.clearBit(i);
+  return DemandedElts;
+}
+
 bool InterleavedAccessInfo::isStrided(int Stride) {
   unsigned Factor = std::abs(Stride);
   return Factor >= 2 && Factor <= MaxInterleaveGroupFactor;