[Mlir-commits] [mlir] 1555d7f - [mlir] subview op lowering for target memrefs with const offset

[Alex Zinenko]

Author: Tobias Gysi
Date: 2020-02-10T17:35:17+01:00
New Revision: 1555d7f729089382520b93634cc24e600fcd21ae

URL: https://github.com/llvm/llvm-project/commit/1555d7f729089382520b93634cc24e600fcd21ae
DIFF: https://github.com/llvm/llvm-project/commit/1555d7f729089382520b93634cc24e600fcd21ae.diff

LOG: [mlir] subview op lowering for target memrefs with const offset

The current standard to llvm conversion pass lowers subview ops only if
dynamic offsets are provided. This commit extends the lowering with a
code path that uses the constant offset of the target memref for the
subview op lowering (see Example 3 of the subview op definition for an
example) if no dynamic offsets are provided.

Differential Revision: https://reviews.llvm.org/D74280

Added: 
    

Modified: 
    mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
    mlir/test/Conversion/StandardToLLVM/convert-to-llvmir.mlir

Removed: 
    


################################################################################
diff  --git a/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp b/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
index 63c8b75f197f..36c98d0e85b1 100644
--- a/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
+++ b/mlir/lib/Conversion/StandardToLLVM/ConvertStandardToLLVM.cpp
@@ -2304,7 +2304,8 @@ struct SubViewOpLowering : public LLVMLegalizationPattern<SubViewOp> {
     // Currently, only rank > 0 and full or no operands are supported. Fail to
     // convert otherwise.
     unsigned rank = sourceMemRefType.getRank();
-    if (viewMemRefType.getRank() == 0 || (rank != dynamicOffsets.size()) ||
+    if (viewMemRefType.getRank() == 0 ||
+        (!dynamicOffsets.empty() && rank != dynamicOffsets.size()) ||
         (!dynamicSizes.empty() && rank != dynamicSizes.size()) ||
         (!dynamicStrides.empty() && rank != dynamicStrides.size()))
       return matchFailure();
@@ -2315,6 +2316,11 @@ struct SubViewOpLowering : public LLVMLegalizationPattern<SubViewOp> {
     if (failed(successStrides))
       return matchFailure();
 
+    // Fail to convert if neither a dynamic nor static offset is available.
+    if (dynamicOffsets.empty() &&
+        offset == MemRefType::getDynamicStrideOrOffset())
+      return matchFailure();
+
     // Create the descriptor.
     MemRefDescriptor sourceMemRef(operands.front());
     auto targetMemRef = MemRefDescriptor::undef(rewriter, loc, targetDescTy);
@@ -2348,14 +2354,18 @@ struct SubViewOpLowering : public LLVMLegalizationPattern<SubViewOp> {
     }
 
     // Offset.
-    Value baseOffset = sourceMemRef.offset(rewriter, loc);
-    for (int i = 0, e = viewMemRefType.getRank(); i < e; ++i) {
-      Value min = dynamicOffsets[i];
-      baseOffset = rewriter.create<LLVM::AddOp>(
-          loc, baseOffset,
-          rewriter.create<LLVM::MulOp>(loc, min, strideValues[i]));
+    if (dynamicOffsets.empty()) {
+      targetMemRef.setConstantOffset(rewriter, loc, offset);
+    } else {
+      Value baseOffset = sourceMemRef.offset(rewriter, loc);
+      for (int i = 0, e = viewMemRefType.getRank(); i < e; ++i) {
+        Value min = dynamicOffsets[i];
+        baseOffset = rewriter.create<LLVM::AddOp>(
+            loc, baseOffset,
+            rewriter.create<LLVM::MulOp>(loc, min, strideValues[i]));
+      }
+      targetMemRef.setOffset(rewriter, loc, baseOffset);
     }
-    targetMemRef.setOffset(rewriter, loc, baseOffset);
 
     // Update sizes and strides.
     for (int i = viewMemRefType.getRank() - 1; i >= 0; --i) {

diff  --git a/mlir/test/Conversion/StandardToLLVM/convert-to-llvmir.mlir b/mlir/test/Conversion/StandardToLLVM/convert-to-llvmir.mlir
index 302aa31e48e0..4c5a4a078a11 100644
--- a/mlir/test/Conversion/StandardToLLVM/convert-to-llvmir.mlir
+++ b/mlir/test/Conversion/StandardToLLVM/convert-to-llvmir.mlir
@@ -815,6 +815,31 @@ func @subview_const_stride(%0 : memref<64x4xf32, affine_map<(d0, d1) -> (d0 * 4
   return
 }
 
+// CHECK-LABEL: func @subview_const_stride_and_offset(
+func @subview_const_stride_and_offset(%0 : memref<64x4xf32, affine_map<(d0, d1) -> (d0 * 4 + d1)>>) {
+  // The last "insertvalue" that populates the memref descriptor from the function arguments.
+  // CHECK: %[[MEMREF:.*]] = llvm.insertvalue %{{.*}}, %{{.*}}[4, 1]
+
+  // CHECK: %[[DESC:.*]] = llvm.mlir.undef : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[DESC0:.*]] = llvm.insertvalue %{{.*}}, %[[DESC]][0] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[DESC1:.*]] = llvm.insertvalue %{{.*}}, %[[DESC0]][1] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[STRIDE0:.*]] = llvm.extractvalue %[[MEMREF]][4, 0] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[STRIDE1:.*]] = llvm.extractvalue %[[MEMREF]][4, 1] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[CST62:.*]] = llvm.mlir.constant(62 : i64)
+  // CHECK: %[[CST3:.*]] = llvm.mlir.constant(3 : i64)
+  // CHECK: %[[CST8:.*]] = llvm.mlir.constant(8 : index)
+  // CHECK: %[[DESC2:.*]] = llvm.insertvalue %[[CST8]], %[[DESC1]][2] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[DESC3:.*]] = llvm.insertvalue %[[CST3]], %[[DESC2]][3, 1] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[CST1:.*]] = llvm.mlir.constant(1 : i64)
+  // CHECK: %[[DESC4:.*]] = llvm.insertvalue %[[CST1]], %[[DESC3]][4, 1] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[DESC5:.*]] = llvm.insertvalue %[[CST62]], %[[DESC4]][3, 0] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  // CHECK: %[[CST4:.*]] = llvm.mlir.constant(4 : i64)
+  // CHECK: llvm.insertvalue %[[CST4]], %[[DESC5]][4, 0] : !llvm<"{ float*, float*, i64, [2 x i64], [2 x i64] }">
+  %1 = subview %0[][][] :
+    memref<64x4xf32, affine_map<(d0, d1) -> (d0 * 4 + d1)>> to memref<62x3xf32, affine_map<(d0, d1) -> (d0 * 4 + d1 + 8)>>
+  return
+}
+
 // -----
 
 module {