[mlir][llvm] Add inalloca attribute to alloca op.

[Moxinilian]

Summary

This revision adds the inalloca attribute to the alloca operation in the LLVMIR dialect.
It also adds tests for import and export.

[gysit]

mlir/test/Dialect/LLVMIR/roundtrip.mlir

329–332

nit: you could drop the new test cases and add the inalloca attribute to the last test case right before the newly introduced code.

mlir/test/Target/LLVMIR/Import/instructions.ll

349

nit: having one test case with inalloca should be sufficient.

mlir/test/Target/LLVMIR/llvmir.mlir

1359

same here except you are testing something different?

[Moxinilian]

mlir/test/Target/LLVMIR/llvmir.mlir

1359

I'm testing that the attribute dictionary still works with inalloca, but yeah I'll just drop that.

[Moxinilian]

Addressed comments.

[gysit]

LGTM!

[Moxinilian]

Improve code style.

[Moxinilian]

Fix silly forgotten argument.

mlir/include/mlir/Dialect/LLVMIR/LLVMOps.td

 def LLVM_FRemOp : LLVM_FloatArithmeticOp<"frem", "FRem">;
 def LLVM_FNegOp : LLVM_UnaryFloatArithmeticOp<
   LLVM_ScalarOrVectorOf<LLVM_AnyFloat>, "fneg", "FNeg">;
 
 // Memory-related operations.
 def LLVM_AllocaOp : LLVM_Op<"alloca">, LLVM_MemOpPatterns {
   let arguments = (ins AnyInteger:$arraySize,
                    OptionalAttr<I64Attr>:$alignment,
-                   OptionalAttr<TypeAttr>:$elem_type);
+                   OptionalAttr<TypeAttr>:$elem_type,
+                   UnitAttr:$inalloca);
   let results = (outs Res<LLVM_AnyPointer, "",
                           [MemAlloc<AutomaticAllocationScopeResource>]>:$res);
   string llvmInstName = "Alloca";
   string llvmBuilder = [{
     auto addrSpace = $_resultType->getPointerAddressSpace();
     llvm::Type *elementType = moduleTranslation.convertType(
         $elem_type ? *$elem_type
                    : op.getType().cast<LLVMPointerType>().getElementType());
     auto *inst = builder.CreateAlloca(elementType, addrSpace, $arraySize);
     }] # setAlignmentCode # [{
+    inst->setUsedWithInAlloca($inalloca);
     $res = inst;
   }];
-  // FIXME: Import attributes.
   string mlirBuilder = [{
     auto *allocaInst = cast<llvm::AllocaInst>(inst);
     Type allocatedType =
       moduleImport.convertType(allocaInst->getAllocatedType());
     unsigned alignment = allocaInst->getAlign().value();
     $res = $_builder.create<LLVM::AllocaOp>(
-      $_location, $_resultType, allocatedType, $arraySize, alignment);
+      $_location, $_resultType, $arraySize,
+      alignment == 0 ? IntegerAttr() : $_builder.getI64IntegerAttr(alignment),
+      TypeAttr::get(allocatedType), allocaInst->isUsedWithInAlloca());
   }];
   let builders = [
     OpBuilder<(ins "Type":$resultType, "Value":$arraySize,
                "unsigned":$alignment),
     [{
       assert(!resultType.cast<LLVMPointerType>().isOpaque() &&
              "pass the allocated type explicitly if opaque pointers are used");
       if (alignment == 0)
         return build($_builder, $_state, resultType, arraySize, IntegerAttr(),
-                     TypeAttr());
+                     TypeAttr(), false);
       build($_builder, $_state, resultType, arraySize,
-        $_builder.getI64IntegerAttr(alignment), TypeAttr());
+        $_builder.getI64IntegerAttr(alignment), TypeAttr(), false);
     }]>,
     OpBuilder<(ins "Type":$resultType, "Type":$elementType, "Value":$arraySize,
                CArg<"unsigned", "0">:$alignment),
     [{
       TypeAttr elemTypeAttr =
           resultType.cast<LLVMPointerType>().isOpaque() ?
           TypeAttr::get(elementType) : TypeAttr();
       build($_builder, $_state, resultType, arraySize,
             alignment == 0 ? IntegerAttr()
                            : $_builder.getI64IntegerAttr(alignment),
-            elemTypeAttr);
+            elemTypeAttr, false);
 
     }]>
     ];
   let hasCustomAssemblyFormat = 1;
   let hasVerifier = 1;
 }
 
 def LLVM_GEPOp : LLVM_Op<"getelementptr", [Pure]> {

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

 //===- LLVMDialect.cpp - LLVM IR Ops and Dialect registration -------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //

 void AllocaOp::print(OpAsmPrinter &p) {
   Type elemTy = getType().cast<LLVM::LLVMPointerType>().getElementType();
   if (!elemTy)
     elemTy = *getElemType();
 
   auto funcTy =
       FunctionType::get(getContext(), {getArraySize().getType()}, {getType()});
 
+  if (getInalloca())
+    p << " inalloca";
+
   p << ' ' << getArraySize() << " x " << elemTy;
   if (getAlignment() && *getAlignment() != 0)
-    p.printOptionalAttrDict((*this)->getAttrs(), {kElemTypeAttrName});
-  else
     p.printOptionalAttrDict((*this)->getAttrs(),
-                            {"alignment", kElemTypeAttrName});
+                            {kElemTypeAttrName, getInallocaAttrName()});
+  else
+    p.printOptionalAttrDict(
+        (*this)->getAttrs(),
+        {getAlignmentAttrName(), kElemTypeAttrName, getInallocaAttrName()});
   p << " : " << funcTy;
 }
 
-// <operation> ::= `llvm.alloca` ssa-use `x` type attribute-dict?
-//                 `:` type `,` type
+// <operation> ::= `llvm.alloca` `inalloca`? ssa-use `x` type
+//                  attribute-dict? `:` type `,` type
 ParseResult AllocaOp::parse(OpAsmParser &parser, OperationState &result) {
   OpAsmParser::UnresolvedOperand arraySize;
   Type type, elemType;
   SMLoc trailingTypeLoc;
+
+  if (succeeded(parser.parseOptionalKeyword("inalloca")))
+    result.addAttribute(getInallocaAttrName(result.name),
+                        UnitAttr::get(parser.getContext()));
+
   if (parser.parseOperand(arraySize) || parser.parseKeyword("x") ||
       parser.parseType(elemType) ||
       parser.parseOptionalAttrDict(result.attributes) || parser.parseColon() ||
       parser.getCurrentLocation(&trailingTypeLoc) || parser.parseType(type))
     return failure();
 
   std::optional<NamedAttribute> alignmentAttr =
       result.attributes.getNamed("alignment");

mlir/test/Dialect/LLVMIR/roundtrip.mlir

func.func @mixed_vect(%arg0: vector<8xf32>, %arg1: vector<4xf32>, %arg2: vector<[4]xf32>) {
   %5 = llvm.intr.vector.extract %arg0[6] : vector<2xf32> from vector<8xf32>
   return
 }
 
 // CHECK-LABEL: @alloca
 func.func @alloca(%size : i64) {
   // CHECK: llvm.alloca %{{.*}} x i32 : (i64) -> !llvm.ptr<i32>
   llvm.alloca %size x i32 {alignment = 0} : (i64) -> (!llvm.ptr<i32>)
-  // CHECK: llvm.alloca %{{.*}} x i32 {alignment = 8 : i64} : (i64) -> !llvm.ptr<i32>
-  llvm.alloca %size x i32 {alignment = 8} : (i64) -> (!llvm.ptr<i32>)
+  // CHECK: llvm.alloca inalloca %{{.*}} x i32 {alignment = 8 : i64} : (i64) -> !llvm.ptr<i32>
+  llvm.alloca inalloca %size x i32 {alignment = 8} : (i64) -> (!llvm.ptr<i32>)
   llvm.return
 }
 
 // CHECK-LABEL: @null
 func.func @null() {
   // CHECK: llvm.mlir.null : !llvm.ptr<i8>
   %0 = llvm.mlir.null : !llvm.ptr<i8>
   // CHECK: llvm.mlir.null : !llvm.ptr<struct<(ptr<func<void (i32, ptr<func<void ()>>)>>, i64)>>
   %1 = llvm.mlir.null : !llvm.ptr<struct<(ptr<func<void (i32, ptr<func<void ()>>)>>, i64)>>
   llvm.return
 }

mlir/test/Target/LLVMIR/Import/instructions.ll

 
 ; CHECK-LABEL: @alloca
 ; CHECK-SAME:  %[[SIZE:[a-zA-Z0-9]+]]
 define ptr @alloca(i64 %size) {
   ; CHECK:  %[[C1:[0-9]+]] = llvm.mlir.constant(1 : i32) : i32
   ; CHECK:  llvm.alloca %[[C1]] x f64 {alignment = 8 : i64} : (i32) -> !llvm.ptr
   ; CHECK:  llvm.alloca %[[SIZE]] x i32 {alignment = 8 : i64} : (i64) -> !llvm.ptr
   ; CHECK:  llvm.alloca %[[SIZE]] x i32 {alignment = 4 : i64} : (i64) -> !llvm.ptr<3>
+  ; CHECK:  llvm.alloca inalloca %[[SIZE]] x i32 {alignment = 4 : i64} : (i64) -> !llvm.ptr
   %1 = alloca double
   %2 = alloca i32, i64 %size, align 8
   %3 = alloca i32, i64 %size, addrspace(3)
+  %4 = alloca inalloca i32, i64 %size
   ret ptr %1
 }
 
 ; // -----
 
 ; CHECK-LABEL: @load_store
 ; CHECK-SAME:  %[[PTR:[a-zA-Z0-9]+]]
 define void @load_store(ptr %ptr) {
   ; CHECK:  %[[V1:[0-9]+]] = llvm.load %[[PTR]] {alignment = 8 : i64} : !llvm.ptr -> f64

mlir/test/Target/LLVMIR/llvmir.mlir

llvm.func @alloca(%size : i64) {
   // Alignment automatically set by the LLVM IR builder when alignment attribute
   // is 0.
   //  CHECK: alloca {{.*}} align 4
   llvm.alloca %size x i32 {alignment = 0} : (i64) -> (!llvm.ptr<i32>)
   // CHECK-NEXT: alloca {{.*}} align 8
   llvm.alloca %size x i32 {alignment = 8} : (i64) -> (!llvm.ptr<i32>)
   // CHECK-NEXT: alloca {{.*}} addrspace(3)
   llvm.alloca %size x i32 {alignment = 0} : (i64) -> (!llvm.ptr<i32, 3>)
+  // CHECK-NEXT: alloca inalloca {{.*}} align 4
+  llvm.alloca inalloca %size x i32 : (i64) -> !llvm.ptr
   llvm.return
 }
 
 // CHECK-LABEL: @constants
 llvm.func @constants() -> vector<4xf32> {
   // CHECK: ret <4 x float> <float 4.2{{0*}}e+01, float 0.{{0*}}e+00, float 0.{{0*}}e+00, float 0.{{0*}}e+00>
   %0 = llvm.mlir.constant(sparse<[0], [4.2e+01]> : vector<4xf32>) : vector<4xf32>
   llvm.return %0 : vector<4xf32>
 }