Add canonicalizer for ViewOp which folds constants into the ViewOp memref shape and layout map strides and offset.

PiperOrigin-RevId: 279088023

1 files changed, 46 insertions, 0 deletions

diff --git a/mlir/test/Transforms/canonicalize.mlir b/mlir/test/Transforms/canonicalize.mlir
index b100f7213f1..8ccf24061b9 100644
--- a/mlir/test/Transforms/canonicalize.mlir
+++ b/mlir/test/Transforms/canonicalize.mlir
@@ -1,5 +1,15 @@
 // RUN: mlir-opt %s -pass-pipeline='func(canonicalize)' | FileCheck %s
 
+#TEST_VIEW_MAP0 = (d0, d1)[s0, s1] -> (d0 * s0 + d1 + s1)
+#TEST_VIEW_MAP1 = (d0, d1, d2)[s0, s1] -> (d0 * s0 + d1 * s1 + d2)
+#TEST_VIEW_MAP2 = (d0, d1)[s0, s1] -> (d0 * 4 + d1 + s1)
+
+// CHECK-DAG: #[[VIEW_MAP0:map[0-9]+]] = (d0, d1) -> (d0 * 11 + d1 + 15)
+// CHECK-DAG: #[[VIEW_MAP1:map[0-9]+]] = (d0, d1)[s0] -> (d0 * 11 + s0 + d1)
+// CHECK-DAG: #[[VIEW_MAP2:map[0-9]+]] = (d0, d1)[s0] -> (d0 * s0 + d1 + 15)
+// CHECK-DAG: #[[VIEW_MAP3:map[0-9]+]] = (d0, d1, d2)[s0] -> (d0 * s0 + d1 * 7 + d2)
+// CHECK-DAG: #[[VIEW_MAP4:map[0-9]+]] = (d0, d1) -> (d0 * 4 + d1 + 15)
+
 // CHECK-LABEL: func @test_subi_zero
 func @test_subi_zero(%arg0: i32) -> i32 {
   // CHECK-NEXT: %c0_i32 = constant 0 : i32
@@ -579,3 +589,39 @@ func @cast_values(%arg0: tensor<*xi32>, %arg1: memref<?xi32>) -> (tensor<2xi32>,
   // CHECK-NEXT: return %0, %1 : tensor<2xi32>, memref<2xi32>
   return %4, %5 : tensor<2xi32>, memref<2xi32>
 }
+
+// CHECK-LABEL: func @view
+func @view(%arg0 : index) {
+  %0 = alloc() : memref<2048xi8>
+  %c7 = constant 7 : index
+  %c11 = constant 11 : index
+  %c15 = constant 15 : index
+
+  // Test: fold constant sizes and offset, update map with static stride/offset.
+  // CHECK: std.view %0[][] : memref<2048xi8> to memref<7x11xf32, #[[VIEW_MAP0]]>
+  %1 = view %0[%c7, %c11][%c15]
+    : memref<2048xi8> to memref<?x?xf32, #TEST_VIEW_MAP0>
+  // Test: fold constant sizes but not offset, update map with static stride.
+  // Test that we do not a fold dynamic dim which is not produced by a constant.
+  // CHECK: std.view %0[][%arg0] : memref<2048xi8> to memref<7x11xf32, #[[VIEW_MAP1]]>
+  %2 = view %0[%c7, %c11][%arg0]
+    : memref<2048xi8> to memref<?x?xf32, #TEST_VIEW_MAP0>
+  // Test: fold constant offset but not sizes, update map with constant offset.
+  // Test that we fold constant offset but not dynamic dims.
+  // CHECK: std.view %0[%arg0, %arg0][] : memref<2048xi8> to memref<?x?xf32, #[[VIEW_MAP2]]>
+  %3 = view %0[%arg0, %arg0][%c15]
+    : memref<2048xi8> to memref<?x?xf32,  #TEST_VIEW_MAP0>
+  // Test: fold one constant dim, no offset, should update with constant
+  // stride on dim 1, but leave dynamic stride on dim 0.
+  // CHECK: std.view %0[%arg0, %arg0][] : memref<2048xi8> to memref<?x?x7xf32, #[[VIEW_MAP3]]>
+  %4 = view %0[%arg0, %arg0, %c7][]
+    : memref<2048xi8> to memref<?x?x?xf32, #TEST_VIEW_MAP1>
+
+  // Test: preserve an existing static dim size while folding a dynamic
+  // dimension and offset.
+  // CHECK: std.view %0[][] : memref<2048xi8> to memref<7x4xf32, #[[VIEW_MAP4]]>
+  %5 = view %0[%c7][%c15]
+    : memref<2048xi8> to memref<?x4xf32, #TEST_VIEW_MAP2>
+
+  return
+}