[Mlir-commits] [clang] [flang] [mlir] [mlir][Interfaces] Single interface method to query constant region-based CF (PR #193486)

[Mehdi Amini]

================
@@ -270,6 +270,51 @@ class RegionBranchPoint {
   Operation *predecessor = nullptr;
 };
 
+/// A bundle of constant-operand information for a `RegionBranchOpInterface`
+/// implementation and any of the region branch terminators in its regions.
+///
+/// This is used by
+/// `RegionBranchOpInterface::getSuccessorRegionsWithConstants` to allow
+/// analyses/transformations to pass along constant operand values for a given
+/// branch point so that the implementation can refine the returned successors.
+/// Operand constants are optional: an implementation that doesn't recognize
+/// the provided constants (or for which no constants are provided) must
+/// return the same successors as the no-constants overload.
+///
+/// For each branch point (the parent op or a region branch terminator), the
+/// associated `ArrayRef<Attribute>` either has the same size as the number of
+/// operands of that op (with a null attribute for non-constant operands), or
+/// is empty (which means: no constant information is available for this
+/// branch point).
+class RegionBranchPointOperandConstants {
+public:
+  /// Default constructor: no constants known for any branch point.
+  RegionBranchPointOperandConstants() = default;
+
+  /// Set the constant operand information for the parent (region branch) op.
+  void setParentOperandConstants(ArrayRef<Attribute> constants) {
+    parentOperandConstants = constants;
+  }
+
+  /// Set the constant operand information for a specific region branch
+  /// terminator.
+  void setTerminatorOperandConstants(Operation *terminator,
+                                     ArrayRef<Attribute> constants) {
+    terminatorOperandConstants[terminator] = constants;
+  }
+
+  /// Returns the constant operand information for the given branch point.
+  /// Returns an empty range if no constants were provided for this point.
+  ArrayRef<Attribute> getOperandConstants(RegionBranchPoint point) const;
+
+private:
+  /// Constant operand information for the parent op of the region branch.
+  ArrayRef<Attribute> parentOperandConstants;
+
+  /// Constant operand information for region branch terminators.
+  DenseMap<Operation *, ArrayRef<Attribute>> terminatorOperandConstants;
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joker-eph wrote:

This looks pretty heavy as an API for something that should be a lightweight API!

https://github.com/llvm/llvm-project/pull/193486