[mlir][bufferization][NFC] More documentation for runOneShotBufferize

[matthias-springer]

No description provided.

[llvmbot]

@llvm/pr-subscribers-mlir-bufferization

@llvm/pr-subscribers-mlir

Author: Matthias Springer (matthias-springer)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/90445.diff

1 Files Affected:

• (modified) mlir/lib/Dialect/Bufferization/Transforms/OneShotAnalysis.cpp (+17-4)

diff --git a/mlir/lib/Dialect/Bufferization/Transforms/OneShotAnalysis.cpp b/mlir/lib/Dialect/Bufferization/Transforms/OneShotAnalysis.cpp
index 531016130d1d8e..2d329a1f3d8892 100644
--- a/mlir/lib/Dialect/Bufferization/Transforms/OneShotAnalysis.cpp
+++ b/mlir/lib/Dialect/Bufferization/Transforms/OneShotAnalysis.cpp
@@ -1382,14 +1382,27 @@ LogicalResult
 bufferization::runOneShotBufferize(Operation *op,
                                    const OneShotBufferizationOptions &options,
                                    BufferizationStatistics *statistics) {
+  // copy-before-write deactivates the analysis. It cannot be used together with
+  // test-analysis-only.
   assert(!(options.copyBeforeWrite && options.testAnalysisOnly) &&
          "invalid combination of bufferization flags");
-  if (!options.copyBeforeWrite) {
-    // If a buffer is copied before every write, no analysis is needed.
+
+  if (options.copyBeforeWrite) {
+    // Copy buffer before each write. No analysis is needed.
+  } else {
+    // Run One-Shot Analysis and insert buffer copies (on the tensor level)
+    // only where needed. This is the default and much more efficient than
+    // copy-before-write.
     if (failed(insertTensorCopies(op, options, statistics)))
       return failure();
+
+    // If test-analysis-only is set, the IR was annotated with RaW conflict
+    // markers (attributes) during One-Shot Analysis.
+    if (options.testAnalysisOnly)
+      return success();
   }
-  if (options.testAnalysisOnly)
-    return success();
+
+  // Bufferize the op and its nested ops. If options.copyBeforeWrite is set,
+  // a new buffer copy is allocated every time a buffer is written to.
   return bufferizeOp(op, options, statistics);
 }