[Mlir-commits] [mlir] [mlir][memref] Clean up `load`/`store` documentation (PR #130569)

[Matthias Springer]

https://github.com/matthias-springer created https://github.com/llvm/llvm-project/pull/130569

Remove references to the Affine dialect. There is a separate `affine.load/store` op.

Also add documentation for `nontemporal`.

>From a836c542869e9592711fa314358d07568607fd64 Mon Sep 17 00:00:00 2001
From: Matthias Springer <mspringer at nvidia.com>
Date: Mon, 10 Mar 2025 10:48:45 +0100
Subject: [PATCH] [mlir][memref] Clean up `load`/`store` documentation

Remove references to the Affine dialect. There is a separate `affine.load` op.

Also add documentation for `nontemporal`.
---
 .../mlir/Dialect/MemRef/IR/MemRefOps.td       | 71 ++++++-------------
 1 file changed, 21 insertions(+), 50 deletions(-)

diff --git a/mlir/include/mlir/Dialect/MemRef/IR/MemRefOps.td b/mlir/include/mlir/Dialect/MemRef/IR/MemRefOps.td
index 4c8a214049ea9..7b6d730293d7f 100644
--- a/mlir/include/mlir/Dialect/MemRef/IR/MemRefOps.td
+++ b/mlir/include/mlir/Dialect/MemRef/IR/MemRefOps.td
@@ -1184,40 +1184,23 @@ def LoadOp : MemRef_Op<"load",
       DeclareOpInterfaceMethods<DestructurableAccessorOpInterface>]> {
   let summary = "load operation";
   let description = [{
-    The `load` op reads an element from a memref specified by an index list. The
-    output of load is a new value with the same type as the elements of the
-    memref. The arity of indices is the rank of the memref (i.e., if the memref
-    loaded from is of rank 3, then 3 indices are required for the load following
-    the memref identifier).
-
-    In an `affine.if` or `affine.for` body, the indices of a load are restricted
-    to SSA values bound to surrounding loop induction variables,
-    [symbols](Affine.md/#dimensions-and-symbols), results of a
-    constant operations, or the result of an
-    `affine.apply` operation that can in turn take as arguments all of the
-    aforementioned SSA values or the recursively result of such an
-    `affine.apply` operation.
+    The `load` op reads an element from a memref at the specified indices.
+
+    The number of indices must match the rank of the memref. The indices must
+    be in-bounds: `0 <= idx < dim_size`
+
+    The single result of `memref.load` is a value with the same type as the
+    element type of the memref.
+
+    A set `nontemporal` attribute indicates that this load is not expected to
+    be reused in the cache. For details, refer to the
+    [https://llvm.org/docs/LangRef.html#load-instruction](LLVM load instruction).
 
     Example:
 
     ```mlir
-    %1 = affine.apply affine_map<(d0, d1) -> (3*d0)> (%i, %j)
-    %2 = affine.apply affine_map<(d0, d1) -> (d1+1)> (%i, %j)
-    %12 = memref.load %A[%1, %2] : memref<8x?xi32, #layout, memspace0>
-
-    // Example of an indirect load (treated as non-affine)
-    %3 = affine.apply affine_map<(d0) -> (2*d0 + 1)>(%12)
-    %13 = memref.load %A[%3, %2] : memref<4x?xi32, #layout, memspace0>
+    %0 = memref.load %A[%a, %b] : memref<8x?xi32, #layout, memspace0>
     ```
-
-    **Context:** The `load` and `store` operations are specifically crafted to
-    fully resolve a reference to an element of a memref, and (in affine
-    `affine.if` and `affine.for` operations) the compiler can follow use-def
-    chains (e.g. through [`affine.apply`](Affine.md/#affineapply-affineapplyop)
-    operations) to precisely analyze references at compile-time using polyhedral
-    techniques. This is possible because of the
-    [restrictions on dimensions and symbols](Affine.md/#restrictions-on-dimensions-and-symbols)
-    in these contexts.
   }];
 
   let arguments = (ins Arg<AnyMemRef, "the reference to load from",
@@ -1817,32 +1800,20 @@ def MemRef_StoreOp : MemRef_Op<"store",
       DeclareOpInterfaceMethods<DestructurableAccessorOpInterface>]> {
   let summary = "store operation";
   let description = [{
-    Store a value to a memref location given by indices. The value stored should
-    have the same type as the elemental type of the memref. The number of
-    arguments provided within brackets need to match the rank of the memref.
-
-    In an affine context, the indices of a store are restricted to SSA values
-    bound to surrounding loop induction variables,
-    [symbols](Affine.md/#restrictions-on-dimensions-and-symbols), results of a
-    `constant` operation, or the result of an
-    [`affine.apply`](Affine.md/#affineapply-affineapplyop) operation that can in
-    turn take as arguments all of the aforementioned SSA values or the
-    recursively result of such an `affine.apply` operation.
+    The `store` op stores an element into a memref at the specified indices.
+    
+    The number of indices must match the rank of the memref. The indices must
+    be in-bounds: `0 <= idx < dim_size`
+
+    A set `nontemporal` attribute indicates that this store is not expected to
+    be reused in the cache. For details, refer to the
+    [https://llvm.org/docs/LangRef.html#store-instruction](LLVM store instruction).
 
     Example:
 
     ```mlir
-    memref.store %100, %A[%1, 1023] : memref<4x?xf32, #layout, memspace0>
+    %0 = memref.store %val, %A[%a, %b] : memref<8x?xi32, #layout, memspace0>
     ```
-
-    **Context:** The `load` and `store` operations are specifically crafted to
-    fully resolve a reference to an element of a memref, and (in polyhedral
-    `affine.if` and `affine.for` operations) the compiler can follow use-def
-    chains (e.g. through [`affine.apply`](Affine.md/#affineapply-affineapplyop)
-    operations) to precisely analyze references at compile-time using polyhedral
-    techniques. This is possible because of the
-    [restrictions on dimensions and symbols](Affine.md/#restrictions-on-dimensions-and-symbols)
-    in these contexts.
   }];
 
   let arguments = (ins AnyType:$value,