Support AllocOp terminal in Linalg::AliasAnalysis.

Now that linalg.view and strided memrefs are unified, there is no reason to
disallow AllocOp in alias analysis. This CLs adds support for AllocOp which allows writing shorter tests that do not require explicitly creating a view for
each operation.

PiperOrigin-RevId: 273303060

mlir/lib/Dialect/Linalg/Analysis/DependenceAnalysis.cpp

@@ -21,6 +21,7 @@
 
 #include "mlir/Dialect/Linalg/Analysis/DependenceAnalysis.h"
 #include "mlir/Dialect/Linalg/IR/LinalgOps.h"
+#include "mlir/Dialect/StandardOps/Ops.h"
 
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
@@ -64,6 +65,10 @@ Value *Aliases::find(Value *v) {
   while (true) {
     if (isa<BlockArgument>(v))
       return v;
+    if (auto alloc = dyn_cast_or_null<AllocOp>(v->getDefiningOp())) {
+      if (isStrided(alloc.getType()))
+        return alloc.getResult();
+    }
     if (auto slice = dyn_cast_or_null<SliceOp>(v->getDefiningOp())) {
       auto it = aliases.insert(std::make_pair(v, find(slice.view())));
       return it.first->second;

mlir/lib/Dialect/Linalg/CMakeLists.txt

@@ -21,5 +21,6 @@ add_dependencies(MLIRLinalg
   MLIRAnalysis
   MLIRLinalgOpsIncGen
   MLIRLinalgLibraryOpsIncGen
+  MLIRStandardOps
   MLIRStandardToLLVM
   )

mlir/test/Dialect/Linalg/fusion.mlir

@@ -366,3 +366,46 @@ func @pointwise(%A: memref<?x?xf32, offset: 0, strides: [?, ?]>, %B: memref<?x?x
 //       CHECK:         addf
 //       CHECK:       linalg.generic
 //       CHECK:         mulf
+
+
+func @pointwise_no_view(%M: index, %N: index) {
+  %c1 = constant 1 : index
+  %c0 = constant 0 : index
+  %c3 = constant 3 : index
+  %c2 = constant 2 : index
+  %A = alloc (%M, %N): memref<?x?xf32>
+  %B = alloc (%M, %N): memref<?x?xf32>
+  %C = alloc (%M, %N): memref<?x?xf32>
+  %D = alloc (%M, %N): memref<?x?xf32>
+  %E = alloc (%M, %N): memref<?x?xf32>
+  linalg.generic #pointwise_2d_trait %A, %A, %B {
+  ^bb0(%e: f32, %arg5: f32, %arg6: f32):   // no predecessors
+    %2 = addf %e, %arg5 : f32
+    linalg.yield %2 : f32
+  }: memref<?x?xf32>, memref<?x?xf32>, memref<?x?xf32>
+  %0 = dim %B, 0 : memref<?x?xf32>
+  %1 = dim %B, 1 : memref<?x?xf32>
+  loop.for %e = %c0 to %0 step %c2 {
+    loop.for %arg5 = %c0 to %1 step %c3 {
+      %2 = affine.apply #map0(%e)
+      %3 = affine.apply #map1(%arg5)
+      %4 = linalg.subview %B[%e, %2, %c1, %arg5, %3, %c1] : memref<?x?xf32>
+      %5 = linalg.subview %C[%e, %2, %c1, %arg5, %3, %c1] : memref<?x?xf32>
+      %6 = linalg.subview %D[%e, %2, %c1, %arg5, %3, %c1] : memref<?x?xf32>
+      linalg.generic #pointwise_2d_trait %4, %5, %6 {
+      ^bb0(%arg6: f32, %arg7: f32, %arg8: f32):       // no predecessors
+        %7 = mulf %arg6, %arg7 : f32
+        linalg.yield %7 : f32
+      }: memref<?x?xf32>, memref<?x?xf32>, memref<?x?xf32>
+    }
+  }
+  return
+}
+// CHECK-LABEL: func @pointwise_no_view
+//       CHECK:   loop.for
+//       CHECK:     loop.for
+//   CHECK-NOT:   loop.for
+//       CHECK:       linalg.generic
+//       CHECK:         addf
+//       CHECK:       linalg.generic
+//       CHECK:         mulf