[Mlir-commits] [mlir] [mlir][spirv] Add support for SwitchOp (PR #168713)

[Jakub Kuderski]

================
@@ -242,6 +242,112 @@ def SPIRV_FunctionCallOp : SPIRV_Op<"FunctionCall", [
   }];
 }
 
+// -----
+
+def SPIRV_SwitchOp : SPIRV_Op<"Switch",
+    [AttrSizedOperandSegments, InFunctionScope,
+     DeclareOpInterfaceMethods<BranchOpInterface, ["getSuccessorForOperands"]>,
+     Pure, Terminator]> {
+  let summary = [{
+    Multi-way branch to one of the operand label <id>.
+  }];
+
+  let description = [{
+    Selector must have a type of OpTypeInt. Selector is compared for equality to
+    the Target literals.
+
+    Default must be the <id> of a label. If Selector does not equal any of the
+    Target literals, control flow branches to the Default label <id>.
+
+    Target must be alternating scalar integer literals and the <id> of a label.
+    If Selector equals a literal, control flow branches to the following label
+    <id>. It is invalid for any two literal to be equal to each other. If Selector
+    does not equal any literal, control flow branches to the Default label <id>.
+    Each literal is interpreted with the type of Selector: The bit width of
+    Selector’s type is the width of each literal’s type. If this width is not a
+    multiple of 32-bits and the OpTypeInt Signedness is set to 1, the literal values
+    are interpreted as being sign extended.
+
+    If Selector is an OpUndef, behavior is undefined.
+
+    This instruction must be the last instruction in a block.
+
+    #### Example:
+
+    ```mlir
+    spirv.Switch %selector : si32, [
+      default: ^bb1(%a : i32),
+      0: ^bb1(%b : i32),
+      1: ^bb3(%c : i32)
+    ]
----------------
kuhar wrote:

Maybe it would be worth expanding this example with contents of the blocks so that it does something?

https://github.com/llvm/llvm-project/pull/168713