[mlir] Fix loop-like interface

[ikulagin]

Using the this pointer inside interface methods is illegal because it breaks concept-based interfaces.
It is necessary to use $_op instead.

[llvmbot]

@llvm/pr-subscribers-mlir

Author: Ivan Kulagin (ikulagin)

Changes

Using the this pointer inside interface methods is illegal because it breaks concept-based interfaces.
It is necessary to use $_op instead.

---

Full diff: https://github.com/llvm/llvm-project/pull/95817.diff

1 Files Affected:

• (modified) mlir/include/mlir/Interfaces/LoopLikeInterface.td (+4-4)

diff --git a/mlir/include/mlir/Interfaces/LoopLikeInterface.td b/mlir/include/mlir/Interfaces/LoopLikeInterface.td
index b748d5e29114a..7db624ba43974 100644
--- a/mlir/include/mlir/Interfaces/LoopLikeInterface.td
+++ b/mlir/include/mlir/Interfaces/LoopLikeInterface.td
@@ -246,7 +246,7 @@ def LoopLikeOpInterface : OpInterface<"LoopLikeOpInterface"> {
     /// If there is a single induction variable return it, otherwise return
     /// std::nullopt.
     ::std::optional<::mlir::Value> getSingleInductionVar() {
-      auto inductionVars = this->getLoopInductionVars();
+      auto inductionVars = $_op.getLoopInductionVars();
       if (inductionVars.has_value() && (*inductionVars).size() == 1)
           return (*inductionVars)[0];
         return std::nullopt;
@@ -254,7 +254,7 @@ def LoopLikeOpInterface : OpInterface<"LoopLikeOpInterface"> {
     /// Return the single lower bound value or attribute if it exists, otherwise
     /// return std::nullopt.
     ::std::optional<::mlir::OpFoldResult> getSingleLowerBound() {
-      auto lowerBounds = this->getLoopLowerBounds();
+      auto lowerBounds = $_op.getLoopLowerBounds();
       if (lowerBounds.has_value() && (*lowerBounds).size() == 1)
           return (*lowerBounds)[0];
       return std::nullopt;
@@ -262,7 +262,7 @@ def LoopLikeOpInterface : OpInterface<"LoopLikeOpInterface"> {
     /// Return the single step value or attribute if it exists, otherwise
     /// return std::nullopt.
     ::std::optional<::mlir::OpFoldResult> getSingleStep() {
-      auto steps = this->getLoopSteps(); 
+      auto steps = $_op.getLoopSteps();
       if (steps.has_value() && (*steps).size() == 1)
           return (*steps)[0];
       return std::nullopt;
@@ -270,7 +270,7 @@ def LoopLikeOpInterface : OpInterface<"LoopLikeOpInterface"> {
     /// Return the single upper bound value or attribute if it exists, otherwise
     /// return std::nullopt.
     ::std::optional<::mlir::OpFoldResult> getSingleUpperBound() {
-      auto upperBounds = this->getLoopUpperBounds();
+      auto upperBounds = $_op.getLoopUpperBounds();
       if (upperBounds.has_value() && (*upperBounds).size() == 1)
           return (*upperBounds)[0];
       return std::nullopt;

[ikulagin]

@joker-eph @makslevental
Please review the suggested fixes

[makslevental]

Was there a fail somewhere? I mean I think you're right but I'm shocked this has never come up before...

[ikulagin]

Was there a fail somewhere? I mean I think you're right but I'm shocked this has never come up before...

Fortunately, the llvm-project codebase uses the buggy methods as follows:

if (auto loop = dyn_cast<LoopLikeOpInterface>(op)) {
    std::optional<Value> iv = loop.getSingleInductionVar();
    ....
}

in this case, the correct implementation of getLoopInductionVars will be called inside the getSingleInductionVar.
If this method were called on a specific operation, for example, AffineForOp, then inside the method getSingleInductionVar the default implementation of the getLoopInductionVars method would be called, and the getSingleInductionVar method will always return std::nullopt