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

[Min-Yih Hsu via llvm-commits]

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@@ -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]);
+  }
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mshockwave wrote:

Yes, it has been generalized now.

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