[SandboxVec] Add TransactionAlwaysRevert pass (#141688)

This patch adds a region pass that reverts the IR state unconditionally.
This is used for testing.

Author: vporpo

llvm/include/llvm/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionAlwaysRevert.h

@@ -0,0 +1,34 @@
+//===- TransactionAlwaysRevert.h --------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This is a region pass that always reverts the transaction without checking
+// its cost. This is mainly used as a final pass in lit tests.
+//
+
+#ifndef LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_TRANSACTIONALWAYSREVERT_H
+#define LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_TRANSACTIONALWAYSREVERT_H
+
+#include "llvm/SandboxIR/Pass.h"
+#include "llvm/SandboxIR/Region.h"
+
+namespace llvm::sandboxir {
+
+class TransactionAlwaysRevert : public RegionPass {
+public:
+  TransactionAlwaysRevert() : RegionPass("tr-revert") {}
+  bool runOnRegion(Region &Rgn, const Analyses &A) final {
+    auto &Tracker = Rgn.getContext().getTracker();
+    bool HasChanges = !Tracker.empty();
+    Tracker.revert();
+    return HasChanges;
+  }
+};
+
+} // namespace llvm::sandboxir
+
+#endif // LLVM_TRANSFORMS_VECTORIZE_SANDBOXVECTORIZER_PASSES_TRANSACTIONALWAYSREVERT_H

llvm/lib/Transforms/Vectorize/SandboxVectorizer/Passes/PassRegistry.def

@@ -22,6 +22,7 @@ REGION_PASS("print-instruction-count", ::llvm::sandboxir::PrintInstructionCount)
 REGION_PASS("print-region", ::llvm::sandboxir::PrintRegion)
 REGION_PASS("tr-save", ::llvm::sandboxir::TransactionSave)
 REGION_PASS("tr-accept", ::llvm::sandboxir::TransactionAlwaysAccept)
+REGION_PASS("tr-revert", ::llvm::sandboxir::TransactionAlwaysRevert)
 REGION_PASS("tr-accept-or-revert", ::llvm::sandboxir::TransactionAcceptOrRevert)
 REGION_PASS("bottom-up-vec", ::llvm::sandboxir::BottomUpVec)
 

llvm/lib/Transforms/Vectorize/SandboxVectorizer/SandboxVectorizerPassBuilder.cpp

@@ -9,6 +9,7 @@
 #include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/SeedCollection.h"
 #include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionAcceptOrRevert.h"
 #include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionAlwaysAccept.h"
+#include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionAlwaysRevert.h"
 #include "llvm/Transforms/Vectorize/SandboxVectorizer/Passes/TransactionSave.h"
 
 namespace llvm::sandboxir {