Using onnx-mlir through incremental stages (#257)

* Add lowering of Vector dialect for lower-all-llvm pass

* Fix generating CallOp instructions when return type is void

* Fix lowering of memref

* Reformat using clang-format

* Record more context.

* Reflow comments.

Co-authored-by: Tian Jin <tjingrant@gmail.com>

src/Conversion/KrnlToLLVM/KrnlToLLVM.cpp

@@ -12,6 +12,7 @@
 #include "mlir/Conversion/SCFToStandard/SCFToStandard.h"
 #include "mlir/Conversion/ShapeToStandard/ShapeToStandard.h"
 #include "mlir/Conversion/StandardToLLVM/ConvertStandardToLLVMPass.h"
+#include "mlir/Conversion/VectorToLLVM/ConvertVectorToLLVM.h"
 #include "mlir/Dialect/Affine/IR/AffineOps.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/Dialect/SCF/SCF.h"
@@ -287,8 +288,7 @@ public:
           rewriter.getIntegerAttr(rewriter.getIntegerType(1), 0));
       //  - Copy constant data into the alloca.
       auto memcpyRef = getOrInsertMemcpy(rewriter, module);
-      rewriter.create<CallOp>(loc, memcpyRef,
+      rewriter.create<CallOp>(loc, memcpyRef, ArrayRef<Type>({}),
-          LLVM::LLVMType::getVoidTy(context),
           ArrayRef<Value>({int8PtrAlloc, i8PtrGlobal, int64Size, isVolatile}));
     } else {
       // Some frequently used types.
@@ -381,7 +381,7 @@ public:
         rewriter.getIntegerAttr(rewriter.getIntegerType(1), 0));
 
     // Memcpy call
-    rewriter.create<CallOp>(loc, memcpyRef, LLVM::LLVMType::getVoidTy(context),
+    rewriter.create<CallOp>(loc, memcpyRef, ArrayRef<Type>({}),
         ArrayRef<Value>({alignedInt8PtrDstMemory, alignedInt8PtrSrcMemory,
             int64Size, isVolatile}));
 
@@ -612,8 +612,19 @@ private:
   // returned, otherwise return nullptr.
   Value callApi(PatternRewriter &rewriter, Location loc, ApiRegistry registry,
       API apiId, ArrayRef<Value> params) const {
+    // To be used as parameters in LLVM::CallOp, voidTy must be converted
+    // to empty list to avoid emission of an SSA value with voidTy. However,
+    // we still keep using LLVM voidTy (as opposed to empty list) when recording
+    // API function signatures in API registry because when declaring API
+    // functions in LLVM IR, the correct way to indicate an output type for
+    // "void" is still LLVM voidTy. Relevant discussion thread:
+    // https://github.com/onnx/onnx-mlir/issues/255.
+    SmallVector<Type, 1> outputTys;
+    auto outputTy = registry.at(apiId).outputTy;
+    if (!outputTy.isVoidTy())
+      outputTys.emplace_back(outputTy);
     auto returnVals =
-        rewriter.create<LLVM::CallOp>(loc, registry.at(apiId).outputTy,
+        rewriter.create<LLVM::CallOp>(loc, ArrayRef<Type>(outputTys),
             registry.at(apiId).symbolRef, ArrayRef<Value>(params));
     if (returnVals.getNumResults() == 1)
       return returnVals.getResult(0);
@@ -642,7 +653,7 @@ private:
     auto memRefTy = memRefPtrTy.getPointerElementTy();
     auto int64Ty = LLVM::LLVMType::getInt64Ty(context);
 
-    Value memRef = rewriter.create<LLVM::LoadOp>(loc, memRefTy, ptrToMemRef);
+    Value memRef = rewriter.create<LLVM::UndefOp>(loc, memRefTy);
 
     // Set dataPtr and alignedDataPtr;
     auto dataPtr =
@@ -859,6 +870,8 @@ void mlir::populateAffineAndKrnlToLLVMConversion(
   populateAffineToStdConversionPatterns(patterns, ctx);
   populateLoopToStdConversionPatterns(patterns, ctx);
   populateShapeToStandardConversionPatterns(patterns, ctx);
+  populateVectorToLLVMMatrixConversionPatterns(typeConverter, patterns);
+  populateVectorToLLVMConversionPatterns(typeConverter, patterns);
   populateStdToLLVMConversionPatterns(typeConverter, patterns);
 
   patterns.insert<KrnlGlobalOpLowering, KrnlPackedConstOpLowering>(
@@ -883,6 +896,7 @@ void ConvertKrnlToLLVMPass::runOnOperation() {
   ConversionTarget target(getContext());
   target.addLegalDialect<LLVM::LLVMDialect>();
   target.addLegalOp<ModuleOp, ModuleTerminatorOp>();
+  target.addIllegalOp<LLVM::DialectCastOp>();
 
   // Lower the MemRef types to a representation in LLVM.
   LowerToLLVMOptions options;

test/mlir/krnl/constant.mlir

@@ -26,7 +26,7 @@ func @test_constant(%arg0 : tensor<1xf32>) -> tensor<*xf32> {
   /// Volatile flag
   // CHECK: [[CONST0:%.+]] = llvm.mlir.constant(false) : !llvm.i1
 
-  // CHECK: llvm.call @llvm.memcpy.p0i8.p0i8.i64([[I8ALLOCA]], [[I8GLOBAL]], [[GLOBAL_SIZE_BYTES]], [[CONST0]]) : (!llvm.ptr<i8>, !llvm.ptr<i8>, !llvm.i64, !llvm.i1) -> !llvm.void
+  // CHECK: llvm.call @llvm.memcpy.p0i8.p0i8.i64([[I8ALLOCA]], [[I8GLOBAL]], [[GLOBAL_SIZE_BYTES]], [[CONST0]]) : (!llvm.ptr<i8>, !llvm.ptr<i8>, !llvm.i64, !llvm.i1) -> ()
 
   /// Prepare data for MemRef insertion.
   // CHECK: [[TYPED_ALLOCA:%.+]] = llvm.bitcast [[ALLOCA]] : !llvm.ptr<array<3 x array<2 x float>>> to !llvm.ptr<float>

test/mlir/krnl/reshape.mlir

@@ -22,6 +22,6 @@ func @test_reshape(%arg0 : tensor<?x10xf32>, %arg1 : tensor<4xi64>) -> tensor<*x
   // CHECK: [[SRC:%.+]] = llvm.bitcast [[EXT_VAL_1]] : !llvm.ptr<float> to !llvm.ptr<i8>
   // CHECK: [[SIZE:%.+]] = llvm.sext %{{.*}} : !llvm.i64 to !llvm.i64
   // CHECK: [[VOLATILE:%.+]] = llvm.mlir.constant(false) : !llvm.i1
-  // CHECK: llvm.call @llvm.memcpy.p0i8.p0i8.i64([[DST]], [[SRC]], [[SIZE]], [[VOLATILE]]) : (!llvm.ptr<i8>, !llvm.ptr<i8>, !llvm.i64, !llvm.i1) -> !llvm.void
+  // CHECK: llvm.call @llvm.memcpy.p0i8.p0i8.i64([[DST]], [[SRC]], [[SIZE]], [[VOLATILE]]) : (!llvm.ptr<i8>, !llvm.ptr<i8>, !llvm.i64, !llvm.i1) -> ()
   // CHECK: llvm.return [[RES]] : !llvm.struct<(ptr<float>, ptr<float>, i64, array<4 x i64>, array<4 x i64>)> 
 }