[Mlir-commits] [mlir] Make isValidLoopInterchangePermutation efficient (PR #128863)

[llvmlistbot at llvm.org]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-mlir-affine

Author: Arnab Dutta  (arnab-polymage)

<details>
<summary>Changes</summary>

Avoid doing dependency checks for the trivial case when size of `loops` is 1.

---
Full diff: https://github.com/llvm/llvm-project/pull/128863.diff


1 Files Affected:

- (modified) mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp (+4-2) 


``````````diff
diff --git a/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp b/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
index 82b96e9876a6f..6833d6583c27a 100644
--- a/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
+++ b/mlir/lib/Dialect/Affine/Utils/LoopUtils.cpp
@@ -1351,10 +1351,12 @@ static bool checkLoopInterchangeDependences(
 /// nested sequence of loops in 'loops' would violate dependences.
 bool mlir::affine::isValidLoopInterchangePermutation(
     ArrayRef<AffineForOp> loops, ArrayRef<unsigned> loopPermMap) {
+  assert(loopPermMap.size() == loops.size() && "invalid loop perm map");
+  unsigned maxLoopDepth = loops.size();
+  if (maxLoopDepth == 1)
+    return true;
   // Gather dependence components for dependences between all ops in loop nest
   // rooted at 'loops[0]', at loop depths in range [1, maxLoopDepth].
-  assert(loopPermMap.size() == loops.size());
-  unsigned maxLoopDepth = loops.size();
   std::vector<SmallVector<DependenceComponent, 2>> depCompsVec;
   getDependenceComponents(loops[0], maxLoopDepth, &depCompsVec);
   return checkLoopInterchangeDependences(depCompsVec, loops, loopPermMap);

``````````

</details>


https://github.com/llvm/llvm-project/pull/128863