[Mlir-commits] [mlir] [mlir][DLTI] Make `getPreferredAlignment` default to `getABIAlignment` (PR #128754)

[Jeff Niu]

https://github.com/Mogball created https://github.com/llvm/llvm-project/pull/128754

Many types don't have a preferred alignment, but often specifying an ABI alignment is required to implement APIs on top of data layouts. Default the preferred alignment to `getABIAlignment` to simplify things.

>From 5ce37bf28f344e37ffb403dee2f6f4165225a600 Mon Sep 17 00:00:00 2001
From: Mogball <jeffniu22 at gmail.com>
Date: Tue, 25 Feb 2025 10:17:34 -0800
Subject: [PATCH] [mlir][DLTI] Make `getPreferredAlignment` default to
 `getABIAlignment`

Many types don't have a preferred alignment, but often specifying an ABI
alignment is required to implement APIs on top of data layouts. Default
the preferred alignment to `getABIAlignment` to simplify things.
---
 mlir/include/mlir/Dialect/LLVMIR/LLVMTypes.td        | 8 +++++---
 mlir/include/mlir/Dialect/Ptr/IR/PtrDialect.td       | 3 ++-
 mlir/include/mlir/Interfaces/DataLayoutInterfaces.td | 6 +++++-
 mlir/test/lib/Dialect/Test/TestTypeDefs.td           | 4 ++--
 4 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMTypes.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMTypes.td
index 0b9e4b9c55738..2ecbf8f50c50c 100644
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMTypes.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMTypes.td
@@ -25,7 +25,8 @@ class LLVMType<string typeName, string typeMnemonic, list<Trait> traits = []>
 //===----------------------------------------------------------------------===//
 
 def LLVMArrayType : LLVMType<"LLVMArray", "array", [
-    DeclareTypeInterfaceMethods<DataLayoutTypeInterface, ["getTypeSize"]>,
+    DeclareTypeInterfaceMethods<DataLayoutTypeInterface,
+                                ["getTypeSize", "getPreferredAlignment"]>,
     DeclareTypeInterfaceMethods<DestructurableTypeInterface>]> {
   let summary = "LLVM array type";
   let description = [{
@@ -124,7 +125,7 @@ def LLVMFunctionType : LLVMType<"LLVMFunction", "func"> {
 def LLVMStructType : LLVMType<"LLVMStruct", "struct", [
   MutableType,
   DeclareTypeInterfaceMethods<DataLayoutTypeInterface,
-    ["areCompatible", "verifyEntries"]>,
+    ["areCompatible", "verifyEntries", "getPreferredAlignment"]>,
   DeclareTypeInterfaceMethods<DestructurableTypeInterface,
     ["getSubelementIndexMap", "getTypeAtIndex"]>
 ]> {
@@ -257,7 +258,8 @@ def LLVMStructType : LLVMType<"LLVMStruct", "struct", [
 
 def LLVMPointerType : LLVMType<"LLVMPointer", "ptr", [
     DeclareTypeInterfaceMethods<DataLayoutTypeInterface, [
-      "getIndexBitwidth", "areCompatible", "verifyEntries"]>]> {
+      "getIndexBitwidth", "areCompatible", "verifyEntries",
+      "getPreferredAlignment"]>]> {
   let summary = "LLVM pointer type";
   let description = [{
     The `!llvm.ptr` type is an LLVM pointer type. This type typically represents
diff --git a/mlir/include/mlir/Dialect/Ptr/IR/PtrDialect.td b/mlir/include/mlir/Dialect/Ptr/IR/PtrDialect.td
index 14d72c3001d91..bc377dcc72e48 100644
--- a/mlir/include/mlir/Dialect/Ptr/IR/PtrDialect.td
+++ b/mlir/include/mlir/Dialect/Ptr/IR/PtrDialect.td
@@ -38,7 +38,8 @@ class Ptr_Type<string name, string typeMnemonic, list<Trait> traits = []>
 def Ptr_PtrType : Ptr_Type<"Ptr", "ptr", [
     MemRefElementTypeInterface,
     DeclareTypeInterfaceMethods<DataLayoutTypeInterface, [
-      "areCompatible", "getIndexBitwidth", "verifyEntries"]>
+      "areCompatible", "getIndexBitwidth", "verifyEntries",
+      "getPreferredAlignment"]>
   ]> {
   let summary = "pointer type";
   let description = [{
diff --git a/mlir/include/mlir/Interfaces/DataLayoutInterfaces.td b/mlir/include/mlir/Interfaces/DataLayoutInterfaces.td
index 0d09b92928fe3..3e4733d252015 100644
--- a/mlir/include/mlir/Interfaces/DataLayoutInterfaces.td
+++ b/mlir/include/mlir/Interfaces/DataLayoutInterfaces.td
@@ -598,7 +598,11 @@ def DataLayoutTypeInterface : TypeInterface<"DataLayoutTypeInterface"> {
       /*retTy=*/"uint64_t",
       /*methodName=*/"getPreferredAlignment",
       /*args=*/(ins "const ::mlir::DataLayout &":$dataLayout,
-                    "::mlir::DataLayoutEntryListRef":$params)
+                    "::mlir::DataLayoutEntryListRef":$params),
+      /*methodBody=*/"",
+      /*defaultImplementation=*/[{
+        return $_type.getABIAlignment(dataLayout, params);
+      }]
     >,
     InterfaceMethod<
       /*description=*/"Returns the bitwidth that should be used when "
diff --git a/mlir/test/lib/Dialect/Test/TestTypeDefs.td b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
index 6335701786ecc..079ffb22e02c2 100644
--- a/mlir/test/lib/Dialect/Test/TestTypeDefs.td
+++ b/mlir/test/lib/Dialect/Test/TestTypeDefs.td
@@ -148,8 +148,8 @@ def TestType : Test_Type<"Test", [
 }
 
 def TestTypeWithLayoutType : Test_Type<"TestTypeWithLayout", [
-  DeclareTypeInterfaceMethods<DataLayoutTypeInterface, ["getIndexBitwidth",
-                                                        "areCompatible"]>
+  DeclareTypeInterfaceMethods<DataLayoutTypeInterface,
+    ["getIndexBitwidth", "areCompatible", "getPreferredAlignment"]>
 ]> {
   let mnemonic = "test_type_with_layout";
   let parameters = (ins "unsigned":$key);