[mlir][linalg] Allow constant exprs in pack/unpack propagation through elementwise

[qedawkins]

Summary

The pack/unpack propagation patterns currently assume all map results
for non-scalar arguments are AffineDimExprs, leading to crashes when the
input operand being packed has constant expressions.

[qedawkins]

lint

[hanchung]

LGTM

mlir/lib/Dialect/Linalg/Transforms/DataLayoutPropagation.cpp

167

We can use dimExpr.getPosition() here

[qedawkins]

rebase and use getPosition

mlir/lib/Dialect/Linalg/Transforms/DataLayoutPropagation.cpp

getOrCreatePackedViewOfOperand(OpBuilder &b, Location loc, PackInfo packInfo,
   SmallVector<AffineExpr> exprs(origIndexingMap.getResults());
   if (genericOp.isScalar(opOperand))
     return std::make_tuple(opOperand->get(),
                            AffineMap::get(numLoops, 0, exprs, b.getContext()));
 
   // Step 1. Construct the information of packing data dimensions; append inner
   // dimensions to the indexing maps for the operand.
   for (auto [index, expr] : llvm::enumerate(exprs)) {
+    if (auto dimExpr = expr.dyn_cast<AffineDimExpr>()) {
       int64_t dimPos = expr.cast<AffineDimExpr>().getPosition();
       domainDimToOperandDim[dimPos] = index;
+      continue;
+    }
+    assert(expr.isa<AffineConstantExpr>() &&
+           "Found non-constant and non-affine dim expression");
   }
   SmallVector<int64_t> innerDimsPos;
   SmallVector<OpFoldResult> innerTileSizes;
   for (auto dimPos : packInfo.tiledDimsPos) {
     if (!domainDimToOperandDim.count(dimPos))
       continue;
     int64_t index = domainDimToOperandDim[dimPos];
     innerTileSizes.push_back(packInfo.domainDimAndTileMapping[dimPos]);
     innerDimsPos.push_back(index);
     exprs.push_back(b.getAffineDimExpr(packInfo.tileToPointMapping[dimPos]));
   }
 
   // Step 2. Handle outer dim permutations.
   SmallVector<int64_t> outerDimsPerm;
   if (!packInfo.outerDimsOnDomainPerm.empty()) {
     outerDimsPerm = computeOuterDims(packInfo.outerDimsOnDomainPerm, exprs);
 
     // Step 2.1: Fold transpose into the linalg.generic.
     SmallVector<int64_t> inversedOuterPerm =
         invertPermutationVector(packInfo.outerDimsOnDomainPerm);
     for (auto i : llvm::seq<unsigned>(0, origIndexingMap.getNumResults())) {
-      int64_t dimPos = exprs[i].cast<AffineDimExpr>().getPosition();
+      if (auto dimExpr = exprs[i].dyn_cast<AffineDimExpr>()) {
+        int64_t dimPos = dimExpr.getPosition();
         exprs[i] = b.getAffineDimExpr(inversedOuterPerm[dimPos]);
+        continue;
+      }
+      assert(exprs[i].isa<AffineConstantExpr>() &&
+             "Attempted to permute non-constant and non-affine dim expression");
     }
     // Step 2.2: Undo the transposition on `exprs` and propagate the
     // transposition on the pack using outerDimsPerm.
     if (!outerDimsPerm.empty()) {
       SmallVector<AffineExpr> auxVec = exprs;
       for (const auto &en : enumerate(outerDimsPerm))
         auxVec[en.index()] = exprs[en.value()];
       exprs = auxVec;

mlir/test/Dialect/Linalg/data-layout-propagation.mlir

 // CHECK-SAME:  into %[[ARG0_EMPTY]]
 // CHECK:       %[[RES:.+]] = linalg.generic
 // CHECK-SAME:    indexing_maps = [#[[MAP0]], #[[MAP1]]]
 // CHECK-SAME:    ins(%[[PACKED_ARG0]]
 // CHECK-SAME:    outs(%[[DEST]]
 
 // -----
 
-#map0 = affine_map<(d0, d1) -> (d0, d1)>
-#map1 = affine_map<(d0, d1) -> (d0)>
-#map2 = affine_map<(d0, d1) -> (d1)>
 func.func @transpose_pack(%arg0: tensor<100x128x200x256xi32>, %arg1: tensor<100xi32>, %arg2: tensor<128xi32>, %dest: tensor<100x200x4x16x16x32xi32>) -> tensor<100x200x4x16x16x32xi32>
 {
   %init_transpose = tensor.empty() : tensor<100x200x128x256xi32>
   %transpose = linalg.generic {
       indexing_maps = [affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, d3)>,
                        affine_map<(d0, d1, d2, d3) -> (d0)>,
                        affine_map<(d0, d1, d2, d3) -> (d1)>,
                        affine_map<(d0, d1, d2, d3) -> (d0, d2, d1, d3)>],

 // CHECK-SAME:  into %[[ARG2_EMPTY]]
 // CHECK:       %[[RES:.+]] = linalg.generic
 // CHECK-SAME:    indexing_maps = [#[[MAP0]], #[[MAP1]], #[[MAP2]], #[[MAP3]]]
 // CHECK-SAME:    ins(%[[PACKED_ARG0]], %[[ARG1]], %[[PACKED_ARG2]]
 // CHECK-SAME:    outs(%[[DEST]]
 
 // -----
 
+func.func @affine_constant_expr_pack(%arg0: tensor<100x128x200x256xi32>, %arg1: tensor<100x1x1x1xi32>, %arg2: tensor<1x128x1x1xi32>, %dest: tensor<100x200x4x16x16x32xi32>) -> tensor<100x200x4x16x16x32xi32>
+{
+  %init_transpose = tensor.empty() : tensor<100x200x128x256xi32>
+  %transpose = linalg.generic {
+      indexing_maps = [affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, d3)>,
+                       affine_map<(d0, d1, d2, d3) -> (d0, 0, 0, 0)>,
+                       affine_map<(d0, d1, d2, d3) -> (0, d1, 0, 0)>,
+                       affine_map<(d0, d1, d2, d3) -> (d0, d2, d1, d3)>],
+      iterator_types = ["parallel", "parallel", "parallel", "parallel"]}
+      ins(%arg0, %arg1, %arg2 : tensor<100x128x200x256xi32>, tensor<100x1x1x1xi32>, tensor<1x128x1x1xi32>)
+      outs(%init_transpose : tensor<100x200x128x256xi32>) {
+    ^bb0(%b0 : i32, %b1 : i32, %b2 : i32, %b3 : i32):
+      %0 = arith.addi %b0, %b1 : i32
+      %1 = arith.addi %0, %b2 : i32
+      linalg.yield %1 : i32
+    } -> tensor<100x200x128x256xi32>
+  %4 = tensor.pack %transpose
+    inner_dims_pos = [3, 2]
+    inner_tiles = [16, 32]
+    into %dest : tensor<100x200x128x256xi32> -> tensor<100x200x4x16x16x32xi32>
+  return %4 : tensor<100x200x4x16x16x32xi32>
+}
+// CHECK-DAG: #[[MAP0:.+]] = affine_map<(d0, d1, d2, d3, d4, d5) -> (d0, d1, d2, d3, d4, d5)>
+// CHECK-DAG: #[[MAP1:.+]] = affine_map<(d0, d1, d2, d3, d4, d5) -> (d0, 0, 0, 0)>
+// CHECK-DAG: #[[MAP2:.+]] = affine_map<(d0, d1, d2, d3, d4, d5) -> (0, d1, 0, 0, d5)>
+// CHECK-DAG: #[[MAP3:.+]] = affine_map<(d0, d1, d2, d3, d4, d5) -> (d0, d2, d1, d3, d4, d5)>
+// CHECK:     func.func @affine_constant_expr_pack
+// CHECK-SAME:   %[[ARG0:[a-zA-Z0-9]+]]
+// CHECK-SAME:   %[[ARG1:[a-zA-Z0-9]+]]
+// CHECK-SAME:   %[[ARG2:[a-zA-Z0-9]+]]
+// CHECK-SAME:   %[[DEST:[a-zA-Z0-9]+]]
+// CHECK:       %[[ARG0_EMPTY:.+]] = tensor.empty() : tensor<100x4x200x16x16x32xi32>
+// CHECK:       %[[PACKED_ARG0:.+]] = tensor.pack %[[ARG0]]
+// CHECK-SAME:    inner_dims_pos = [3, 1] inner_tiles = [16, 32]
+// CHECK-SAME:  into %[[ARG0_EMPTY]]
+// CHECK:       %[[ARG2_EMPTY:.+]] = tensor.empty() : tensor<1x4x1x1x32xi32>
+// CHECK:       %[[PACKED_ARG2:.+]] = tensor.pack %[[ARG2]]
+// CHECK-SAME:    inner_dims_pos = [1] inner_tiles = [32]
+// CHECK-SAME:  into %[[ARG2_EMPTY]]
+// CHECK:       %[[RES:.+]] = linalg.generic
+// CHECK-SAME:    indexing_maps = [#[[MAP0]], #[[MAP1]], #[[MAP2]], #[[MAP3]]]
+// CHECK-SAME:    ins(%[[PACKED_ARG0]], %[[ARG1]], %[[PACKED_ARG2]]
+// CHECK-SAME:    outs(%[[DEST]]
+
+// -----
+
 #map0 = affine_map<(d0, d1) -> (d0, d1)>
 #map1 = affine_map<(d0, d1) -> (d0)>
 #map2 = affine_map<(d0, d1) -> (d1)>
 func.func @transpose_pack_with_outer_dims(%arg0: tensor<100x128x200x256xi32>, %arg1: tensor<100xi32>, %arg2: tensor<128xi32>, %dest: tensor<200x4x16x100x16x32xi32>) -> tensor<200x4x16x100x16x32xi32>
 {
   %init_transpose = tensor.empty() : tensor<100x200x128x256xi32>
   %transpose = linalg.generic {
       indexing_maps = [affine_map<(d0, d1, d2, d3) -> (d0, d1, d2, d3)>,