[Mlir-commits] [mlir] [mlir][affine] Fix inverted epilogue check in affineForOpBodySkew (PR #217553)

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llvmorg-github-actions[bot] wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir-affine

Author: Babar Khan  (BabarZKhan)

<details>
<summary>Changes</summary>

So, my understanding is, when `unrollPrologueEpilogue` is enabled, `affineForOpBodySkew` aims to fully unroll both the generated prologue and epilogue.  The epilogue condition incorrectly checks `!epilogue`, may be causing valid epilogues to be skipped and passing a null operation to `loopUnrollFull.`

**trivial fix:**
replace the condition with `epilogue && epilogue != prologue`.  So that , a valid epilogue is unrolled exactly once.


---
Full diff: https://github.com/llvm/llvm-project/pull/217553.diff


1 Files Affected:

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


``````````diff
diff --git a/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp b/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
index 90bc57e950cf1..293356b164a36 100644
--- a/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
+++ b/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
@@ -352,7 +352,7 @@ LogicalResult mlir::affine::affineForOpBodySkew(AffineForOp forOp,
 
   if (unrollPrologueEpilogue && prologue)
     (void)loopUnrollFull(prologue);
-  if (unrollPrologueEpilogue && !epilogue && epilogue != prologue)
+  if (unrollPrologueEpilogue && epilogue && epilogue != prologue)
     (void)loopUnrollFull(epilogue);
 
   return success();

``````````

</details>


https://github.com/llvm/llvm-project/pull/217553