[llvm] [IA][RISCV] Add support for vp.load/vp.store with shufflevector (PR #135445)

[Luke Lau via llvm-commits]

================
@@ -454,27 +496,77 @@ bool InterleavedAccessImpl::tryReplaceExtracts(
 }
 
 bool InterleavedAccessImpl::lowerInterleavedStore(
-    StoreInst *SI, SmallSetVector<Instruction *, 32> &DeadInsts) {
-  if (!SI->isSimple())
-    return false;
+    Instruction *Store, SmallSetVector<Instruction *, 32> &DeadInsts) {
+  Value *StoredValue;
+  if (auto *SI = dyn_cast<StoreInst>(Store)) {
+    if (!SI->isSimple())
+      return false;
+    StoredValue = SI->getValueOperand();
+  } else if (auto *VPStore = dyn_cast<VPIntrinsic>(Store)) {
+    assert(VPStore->getIntrinsicID() == Intrinsic::vp_store);
+    // Require a constant mask.
+    if (!isa<ConstantVector>(VPStore->getArgOperand(2)))
+      return false;
+    StoredValue = VPStore->getArgOperand(0);
+  } else {
+    llvm_unreachable("unsupported store operation");
+  }
 
-  auto *SVI = dyn_cast<ShuffleVectorInst>(SI->getValueOperand());
+  auto *SVI = dyn_cast<ShuffleVectorInst>(StoredValue);
   if (!SVI || !SVI->hasOneUse() || isa<ScalableVectorType>(SVI->getType()))
     return false;
 
+  unsigned NumStoredElements =
+      cast<FixedVectorType>(SVI->getType())->getNumElements();
   // Check if the shufflevector is RE-interleave shuffle.
   unsigned Factor;
   if (!isReInterleaveMask(SVI, Factor, MaxFactor))
     return false;
+  assert(NumStoredElements % Factor == 0 &&
+         "number of stored element should be a multiple of Factor");
+
+  if (auto *VPStore = dyn_cast<VPIntrinsic>(Store)) {
+    unsigned LaneMaskLen = NumStoredElements / Factor;
+    Value *LaneMask = getMask(VPStore->getArgOperand(2), Factor,
----------------
lukel97 wrote:

```suggestion
    Value *LaneMask = getMask(VPStore->getMaskParam(), Factor,
```

https://github.com/llvm/llvm-project/pull/135445