[llvm] [IA][RISCV] Support VP intrinsics in InterleavedAccessPass (PR #120490)

[Min-Yih Hsu via llvm-commits]

================
@@ -248,6 +249,196 @@ static bool isReInterleaveMask(ShuffleVectorInst *SVI, unsigned &Factor,
   return false;
 }
 
+// For an (de)interleave tree like this:
+//
+//   A   C B   D
+//   |___| |___|
+//     |_____|
+//        |
+//     A B C D
+//
+//  We will get ABCD at the end while the leaf operands/results
+//  are ACBD, which are also what we initially collected in
+//  getVectorInterleaveFactor / getVectorDeinterleaveFactor. But TLI
+//  hooks (e.g. lowerInterleavedScalableLoad) expect ABCD, so we need
+//  to reorder them by interleaving these values.
+static void interleaveLeafValues(SmallVectorImpl<Value *> &Leaves) {
+  unsigned Factor = Leaves.size();
+  assert(isPowerOf2_32(Factor) && Factor <= 8 && Factor > 1);
+
+  if (Factor == 2)
+    return;
+
+  SmallVector<Value *, 8> Buffer;
+  if (Factor == 4) {
+    for (unsigned SrcIdx : {0, 2, 1, 3})
+      Buffer.push_back(Leaves[SrcIdx]);
+  } else {
+    // Factor of 8.
+    //
+    //  A E C G B F D H
+    //  |_| |_| |_| |_|
+    //   |___|   |___|
+    //     |_______|
+    //         |
+    //  A B C D E F G H
+    for (unsigned SrcIdx : {0, 4, 2, 6, 1, 5, 3, 7})
+      Buffer.push_back(Leaves[SrcIdx]);
+  }
+
+  llvm::copy(Buffer, Leaves.begin());
+}
+
+static unsigned getVectorInterleaveFactor(IntrinsicInst *II,
+                                          SmallVectorImpl<Value *> &Operands) {
+  if (II->getIntrinsicID() != Intrinsic::vector_interleave2)
+    return 0;
+
+  unsigned Factor = 0;
+
+  // Visit with BFS
+  SmallVector<IntrinsicInst *, 8> Queue;
+  Queue.push_back(II);
+  while (!Queue.empty()) {
+    IntrinsicInst *Current = Queue.front();
+    Queue.erase(Queue.begin());
+
+    for (unsigned I = 0; I < 2; ++I) {
+      Value *Op = Current->getOperand(I);
+      if (auto *OpII = dyn_cast<IntrinsicInst>(Op))
+        if (OpII->getIntrinsicID() == Intrinsic::vector_interleave2) {
+          Queue.push_back(OpII);
+          continue;
+        }
+
+      // If this is not a perfectly balanced tree, the leaf
+      // result types would be different.
+      if (!Operands.empty() && Op->getType() != Operands.back()->getType())
+        return 0;
+
+      ++Factor;
+      Operands.push_back(Op);
+    }
+  }
+
+  // Currently we only recognize power-of-two factors.
+  // FIXME: should we assert here instead?
+  if (Factor <= 1 || !isPowerOf2_32(Factor))
+    return 0;
+
+  interleaveLeafValues(Operands);
+  return Factor;
+}
+
+/// Check the interleaved mask
+///
+/// - if a value within the optional is non-nullptr, the value corresponds to
+///   deinterleaved mask
+/// - if a value within the option is nullptr, the value corresponds to all-true
+///   mask
+/// - return nullopt if mask cannot be deinterleaved
+static std::optional<Value *> getMask(Value *WideMask, unsigned Factor) {
+  using namespace llvm::PatternMatch;
+  if (auto *IMI = dyn_cast<IntrinsicInst>(WideMask)) {
+    SmallVector<Value *, 8> Operands;
+    if (unsigned MaskFactor = getVectorInterleaveFactor(IMI, Operands)) {
+      assert(!Operands.empty());
+      if (MaskFactor == Factor &&
+          std::equal(Operands.begin(), Operands.end(), Operands.begin()))
+        return Operands.front();
+    }
+  }
+  if (match(WideMask, m_AllOnes()))
+    return nullptr;
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mshockwave wrote:

> So you might be able to get away with only emitting the masked intrinsic.

It's done now

https://github.com/llvm/llvm-project/pull/120490