[Matrix] Mark matrix memory intrinsics as argmemonly/write|read mem.

matrix.columnwise.load and matrix.columnwise.store only access memory
through the argument pointers. Also matrix.columnwise.store only writes
memory.

(Cherry-picked from 8c681f5)

Author: fhahn

llvm/include/llvm/IR/Intrinsics.td

@@ -1272,16 +1272,17 @@ def int_matrix_columnwise_load : Intrinsic<[llvm_anyvector_ty],
                                             llvm_i32_ty,
                                             llvm_i32_ty,
                                             llvm_i32_ty],
-                                           [IntrReadMem, IntrWillReturn,
-                                            ImmArg<2>, ImmArg<3>]>;
+                                           [IntrArgMemOnly, IntrReadMem,
+                                            IntrWillReturn, ImmArg<2>, ImmArg<3>]>;
 
 def int_matrix_columnwise_store : Intrinsic<[],
                                             [llvm_anyvector_ty,
                                              LLVMAnyPointerType<LLVMMatchType<0>>,
                                              llvm_i32_ty,
                                              llvm_i32_ty,
                                              llvm_i32_ty],
-                                            [WriteOnly<1>, IntrWillReturn,
+                                            [IntrArgMemOnly, IntrWillReturn,
+                                             IntrWriteMem, WriteOnly<1>,
                                              ImmArg<3>, ImmArg<4>]>;
 
 //===---------- Intrinsics to control hardware supported loops ----------===//

llvm/test/Transforms/LowerMatrixIntrinsics/strided-load-double.ll

@@ -66,3 +66,9 @@ entry:
   %load = call <8 x double> @llvm.matrix.columnwise.load.v8f64(<8 x double>* %in, i32 %stride, i32 4, i32 2)
   ret <8 x double> %load
 }
+
+; CHECK: declare <9 x double> @llvm.matrix.columnwise.load.v9f64.p0v9f64(<9 x double>*, i32, i32 immarg, i32 immarg) [[READONLY:#[0-9]]]
+
+; CHECK: declare <8 x double> @llvm.matrix.columnwise.load.v8f64.p0v8f64(<8 x double>*, i32, i32 immarg, i32 immarg) [[READONLY]]
+
+; CHECK: attributes [[READONLY]] = { argmemonly nounwind readonly willreturn }

llvm/test/Transforms/LowerMatrixIntrinsics/strided-store-double.ll

@@ -66,3 +66,9 @@ define void @strided_store_2x3(<10 x double> %in, double* %out) {
 }
 
 declare void @llvm.matrix.columnwise.store.v10f64(<10 x double>, double*, i32, i32, i32)
+
+; CHECK: declare void @llvm.matrix.columnwise.store.v6f64.p0f64(<6 x double>, double* writeonly, i32, i32 immarg, i32 immarg) [[WRITEONLY:#[0-9]]]
+
+; CHECK: declare void @llvm.matrix.columnwise.store.v10f64.p0f64(<10 x double>, double* writeonly, i32, i32 immarg, i32 immarg) [[WRITEONLY]]
+
+; CHECK: attributes [[WRITEONLY]] = { argmemonly nounwind willreturn writeonly }