[Mlir-commits] [mlir] [mlir] Restore fullyComposeAffineMapAndOperands in simplifyConstrainedMinMaxOp (PR #233743)

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@llvm/pr-subscribers-mlir

Author: xshang-synaptics

<details>
<summary>Changes</summary>

Commit d725513e7d92 (#<!-- -->189246, fixing #<!-- -->127436) hardened simplifyConstrainedMinMaxOp against null operand values. As a side effect of that refactor it dropped the operand composition:

    -  SmallVector<Value> operands = ...getOperands();
    -  affine::fullyComposeAffineMapAndOperands(&map, &operands);
    +  ValueRange operands = op->getOperands();

Without the composition, the constraint solver can no longer fold nested affine.min/max chains whose operands are themselves affine min/max/apply results (they become opaque dims it cannot reason through). A boundary clamp like min(N - offset, size) then stays symbolic even when the enclosing loop bounds make it provably constant. Direct callers of this utility (e.g. IREE's FoldAffineMinInDistributedLoops) do not run affine canonicalization beforehand, so the uncomposed operands leak through and the simplification silently fails.

Restore the composition while keeping the #<!-- -->127436 null-operand handling (that block guards the appended internal constraint dims, which are null-valued in either formulation and is a genuine UB fix we must not regress).

---
Full diff: https://github.com/llvm/llvm-project/pull/233743.diff


1 Files Affected:

- (modified) mlir/lib/Dialect/Affine/Analysis/Utils.cpp (+4-1) 


``````````diff
diff --git a/mlir/lib/Dialect/Affine/Analysis/Utils.cpp b/mlir/lib/Dialect/Affine/Analysis/Utils.cpp
index 0e036dfedbf52e..6bfa5929705b64 100644
--- a/mlir/lib/Dialect/Affine/Analysis/Utils.cpp
+++ b/mlir/lib/Dialect/Affine/Analysis/Utils.cpp
@@ -2318,7 +2318,10 @@ FailureOr<AffineValueMap> mlir::affine::simplifyConstrainedMinMaxOp(
   Builder builder(ctx);
   AffineMap map =
       isMin ? cast<AffineMinOp>(op).getMap() : cast<AffineMaxOp>(op).getMap();
-  ValueRange operands = op->getOperands();
+  SmallVector<Value> operands =
+      isMin ? cast<AffineMinOp>(op).getOperands()
+            : cast<AffineMaxOp>(op).getOperands();
+  affine::fullyComposeAffineMapAndOperands(&map, &operands);
   unsigned numResults = map.getNumResults();
 
   // Add a few extra dimensions.

``````````

</details>


https://github.com/llvm/llvm-project/pull/233743