[Mlir-commits] [mlir] [mlir][vector] Allow signless integer element types in `vector.step` (PR #205142)

[Jakub Kuderski]

================
@@ -3019,27 +3019,38 @@ def Vector_ScanOp :
 // VectorStepOp
 //===----------------------------------------------------------------------===//
 
+// Allowed element type for `vector.step`: `index`, or a signless integer of at
+// least 8 bits.
+def VectorStepElementType : Type<
+  CPred<"::llvm::isa<::mlir::IndexType>($_self) || ($_self.isSignlessInteger() && $_self.getIntOrFloatBitWidth() >= 8)">,
+  "index or signless integer of at least 8 bits">;
+
 def Vector_StepOp : Vector_Op<"step", [
     Pure,
     DeclareOpInterfaceMethods<VectorUnrollOpInterface>,
     DeclareOpInterfaceMethods<InferIntRangeInterface, ["inferResultRanges"]>
   ]> {
   let summary = "A linear sequence of values from 0 to N";
   let description = [{
-    A `step` operation produces an index vector, i.e. a 1-D vector of values of
-    index type that represents a linear sequence from 0 to N-1, where N is the
-    number of elements in the `result` vector.
+    A `step` operation produces a 1-D vector representing a linear sequence from
+    0 to N-1, where N is the number of elements in the `result` vector.
+
+    The result element type must be `index` or a signless integer of at least 8
+    bits. If the sequence value exceeds the allowed limit for the element type
+    then the result for that lane is truncated.
 
     Supports fixed-width and scalable vectors.
 
     Examples:
 
     ```mlir
-    %0 = vector.step : vector<4xindex> ; [0, 1, 2, 3]
-    %1 = vector.step : vector<[4]xindex> ; [0, 1, .., <vscale * 4 - 1>]
+    %0 = vector.step : vector<4xindex>   ; [0, 1, 2, 3]
+    %1 = vector.step : vector<4xi32>     ; [0, 1, 2, 3]
+    %2 = vector.step : vector<258xi8>    ; [0, 1, .., 255, 0, 1]
+    %3 = vector.step : vector<[4]xindex> ; [0, 1, .., <vscale * 4 - 1>]
----------------
kuhar wrote:

mlir uses `//` for inline comments

https://github.com/llvm/llvm-project/pull/205142