[llvm] [MemoryLocation] Support strided matrix loads / stores (PR #163368)

[Nikita Popov via llvm-commits]

================
@@ -288,6 +288,34 @@ MemoryLocation MemoryLocation::getForArgument(const CallBase *Call,
                             LocationSize::precise(DL.getTypeStoreSize(
                                 II->getArgOperand(1)->getType())),
                             AATags);
+    case Intrinsic::matrix_column_major_load:
+    case Intrinsic::matrix_column_major_store: {
+      bool IsLoad = II->getIntrinsicID() == Intrinsic::matrix_column_major_load;
+      assert(ArgIdx == (IsLoad ? 0 : 1) && "Invalid argument index");
+
+      auto *Stride = dyn_cast<ConstantInt>(II->getArgOperand(IsLoad ? 1 : 2));
+      uint64_t Rows =
+          cast<ConstantInt>(II->getArgOperand(IsLoad ? 3 : 4))->getZExtValue();
+      uint64_t Cols =
+          cast<ConstantInt>(II->getArgOperand(IsLoad ? 4 : 5))->getZExtValue();
+
+      // The stride is dynamic, so there's nothing we can say.
+      if (!Stride)
+        return MemoryLocation(Arg, LocationSize::afterPointer(), AATags);
+
+      uint64_t ConstStride = Stride->getZExtValue();
+      auto *VT = cast<VectorType>(IsLoad ? II->getType()
+                                         : II->getArgOperand(0)->getType());
+      assert(Cols != 0 && "Matrix cannot have 0 columns");
+      TypeSize Size = DL.getTypeStoreSize(VT->getScalarType()) *
----------------
nikic wrote:

```suggestion
      TypeSize Size = DL.getTypeAllocSize(VT->getScalarType()) *
```
Not that it is likely to make a difference here, but my understanding is that this is a GEP stride, which uses the alloc size.

https://github.com/llvm/llvm-project/pull/163368