Add a test with affine.if to make sure it doesn't get a symbol

Author: cferry-AMD

mlir/test/Dialect/Linalg/affine-if.mlir

@@ -0,0 +1,27 @@
+// RUN: mlir-opt -canonicalize %s | FileCheck %s
+
+// Check that linalg.index does not cause folding of affine.if set to
+// a symbolic set.
+
+// CHECK: = affine_set<(d0) : (-d0 + 5 >= 0)>
+#set = affine_set<(d0) : (-d0 + 5 >= 0)>
+
+func.func @linalg_index_affine_if(%in: tensor<10xf32>) -> tensor<10xf32> {
+  %empty = tensor.empty() : tensor<10xf32>
+  %out = linalg.generic {
+      indexing_maps = [affine_map<(i) -> (i)>, affine_map<(i) -> (i)>], 
+      iterator_types = ["parallel"]}
+    ins(%in : tensor<10xf32>)
+    outs(%empty : tensor<10xf32>) {
+      ^bb0(%a: f32, %b: f32):
+        %c42f = arith.constant 42.0 : f32
+        %i = linalg.index 0 : index
+        %ret = affine.if #set(%i) -> f32 {
+          affine.yield %a : f32
+        } else {
+          affine.yield %c42f : f32
+        }
+        linalg.yield %ret : f32
+    } -> tensor<10xf32>
+  return %out : tensor<10xf32>
+}