[llvm] [OpenMP] [IR Builder] Changes to Support Scan Operation (PR #136035)

[Anchu Rajendran S via llvm-commits]

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@@ -750,6 +755,42 @@ class OpenMPIRBuilder {
                       LoopBodyGenCallbackTy BodyGenCB, Value *TripCount,
                       const Twine &Name = "loop");
 
+  /// Generator for the control flow structure of an OpenMP canonical loops if
+  /// the parent directive has an `inscan` modifier specified.
+  /// If the `inscan` modifier is specified, the region of the parent is
+  /// expected to have a `scan` directive. Based on the clauses in
+  /// scan directive, the body of the loop is split into two loops: Input loop
+  /// and Scan Loop. Input loop contains the code generated for input phase of
+  /// scan and Scan loop contains the code generated for scan phase of scan.
+  /// From the bodyGen callback of these loops, `createScan` would be called
+  /// when a scan directive is encountered from the loop body. `createScan`
+  /// based on whether 1. inclusive or exclusive scan is specified and, 2. input
+  /// loop or scan loop is generated, lowers the body of the for loop
+  /// accordingly.
+  ///
+  /// \param Loc       The insert and source location description.
+  /// \param BodyGenCB Callback that will generate the loop body code.
+  /// \param Start     Value of the loop counter for the first iterations.
+  /// \param Stop      Loop counter values past this will stop the loop.
+  /// \param Step      Loop counter increment after each iteration; negative
+  ///                  means counting down.
+  /// \param IsSigned  Whether Start, Stop and Step are signed integers.
+  /// \param InclusiveStop Whether \p Stop itself is a valid value for the loop
+  ///                      counter.
+  /// \param ComputeIP Insertion point for instructions computing the trip
+  ///                  count. Can be used to ensure the trip count is available
+  ///                  at the outermost loop of a loop nest. If not set,
+  ///                  defaults to the preheader of the generated loop.
+  /// \param Name      Base name used to derive BB and instruction names.
+  /// \param ScanRedInfo  Pointer to the ScanInfo objected created using
+  /// `ScanInfoInitialize`.
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anchuraj wrote:

Updated.

https://github.com/llvm/llvm-project/pull/136035