[AArch64][SVE] Implement masked load intrinsics

Summary:
Adds support for codegen of masked loads, with non-extending,
zero-extending and sign-extending variants.

Reviewers: huntergr, rovka, greened, dmgreen

Reviewed By: dmgreen

Subscribers: dmgreen, samparker, tschuett, kristof.beyls, hiraditya, rkruppe, psnobl, cfe-commits, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68877

3 files changed, 14 insertions, 7 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 45947939482..6b30ebecbea 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9108,6 +9108,8 @@ SDValue DAGCombiner::CombineExtLoad(SDNode *N) {
   if (!TLI.isLoadExtLegalOrCustom(ExtType, SplitDstVT, SplitSrcVT))
     return SDValue();
 
+  assert(!DstVT.isScalableVector() && "Unexpected scalable vector type");
+
   SDLoc DL(N);
   const unsigned NumSplits =
       DstVT.getVectorNumElements() / SplitDstVT.getVectorNumElements();
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 4ffc55c62f2..0c30ea0108c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1279,7 +1279,9 @@ SDValue SelectionDAG::getConstant(const ConstantInt &Val, const SDLoc &DL,
   }
 
   SDValue Result(N, 0);
-  if (VT.isVector())
+  if (VT.isScalableVector())
+    Result = getSplatVector(VT, DL, Result);
+  else if (VT.isVector())
     Result = getSplatBuildVector(VT, DL, Result);
 
   return Result;
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 8c15563fcd2..51f5b1998bb 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4462,12 +4462,15 @@ void SelectionDAGBuilder::visitMaskedLoad(const CallInst &I, bool IsExpanding) {
   const MDNode *Ranges = I.getMetadata(LLVMContext::MD_range);
 
   // Do not serialize masked loads of constant memory with anything.
-  bool AddToChain =
-      !AA || !AA->pointsToConstantMemory(MemoryLocation(
-                 PtrOperand,
-                 LocationSize::precise(
-                     DAG.getDataLayout().getTypeStoreSize(I.getType())),
-                 AAInfo));
+  MemoryLocation ML;
+  if (VT.isScalableVector())
+    ML = MemoryLocation(PtrOperand);
+  else
+    ML = MemoryLocation(PtrOperand, LocationSize::precise(
+                           DAG.getDataLayout().getTypeStoreSize(I.getType())),
+                           AAInfo);
+  bool AddToChain = !AA || !AA->pointsToConstantMemory(ML);
+
   SDValue InChain = AddToChain ? DAG.getRoot() : DAG.getEntryNode();
 
   MachineMemOperand *MMO =