[Mlir-commits] [mlir] [OpenMP][MLIR] Add omp.canonical_loop operation, !omp.cli type, omp.new_cli operation (PR #71712)

[Kiran Chandramohan]

================
@@ -405,6 +405,170 @@ def SingleOp : OpenMP_Op<"single", [AttrSizedOperandSegments]> {
   let hasVerifier = 1;
 }
 
+//===---------------------------------------------------------------------===//
+// OpenMP Canonical Loop Info Type
+//===---------------------------------------------------------------------===//
+
+def CanonicalLoopInfoType : OpenMP_Type<"CanonicalLoopInfo", "cli"> {
+  let summary = "Type for representing a reference to a canonical loop";
+  let description = [{
+    A variable of type CanonicalLoopInfo refers to an OpenMP-compatible
+    canonical loop in the same function. Variables of this type are not
+    available at runtime and therefore cannot be used by the program itself,
+    i.e. an opaque type. It is similar to the transform dialect's
+    `!transform.interface` type, but instead of implementing an interface
+    for each transformation, the OpenMP dialect itself defines possible
+    operations on this type.
+
+    A CanonicalLoopInfo variable can
+
+    1. passed to omp.canonical_loop to assiciate the loop to that variable
+    2. passed to omp operations that take a CanonicalLoopInfo argument,
+       such as `omp.unroll`.
+
+    A CanonicalLoopInfo variable can not
+
+    1. be returned from a function,
+    2. passed to operations that are not specifically designed to take a
+       CanonicalLoopInfo, including AnyType.
+
+    A CanonicalLoopInfo variable directly corresponds to an object of
+    OpenMPIRBuilder's CanonicalLoopInfo struct when lowering to LLVM-IR.
+  }];
+}
+
+//===---------------------------------------------------------------------===//
+// OpenMP Canonical Loop Info Operation
+//===---------------------------------------------------------------------===//
+
+def NewCliOp : OpenMP_Op<"new_cli"> {
+  let summary = "Create a new Canonical Loop Info value.";
+  let description = [{
+    Create a new CLI that can be passed as an argument to a CanonicalLoopOp
+    and to loop transformation operations to handle dependencies between
+    loop transformation operations.
+    }];
+    let results = (outs CanonicalLoopInfoType:$result);
+    let assemblyFormat = [{
+        attr-dict `:` type($result)
+    }];
+}
+
+
+//===---------------------------------------------------------------------===//
+// OpenMP Canonical Loop Operation
+//===---------------------------------------------------------------------===//
+def CanonicalLoopOp : OpenMP_Op<"canonical_loop", [SingleBlockImplicitTerminator<"omp::YieldOp">]> {
----------------
kiranchandramohan wrote:

`SingleBlock` would not work at the LLVM dialect level where there would be branches. It will also not work at the FIR level in Flang if there is unstructured code (do-while, jumps etc) in the body of the loop. 

https://github.com/llvm/llvm-project/pull/71712