https://github.com/justinfargnoli created https://github.com/llvm/llvm-project/pull/69043
Fix for a crash reported in #64975.
The crash occurs in the cast located [here](https://github.com/llvm/llvm-project/blob/ece5dd101c7e4dc2fd23428abd312f75fd3d3eaf/mlir/lib/Analysis/DataFlow/DeadCodeAnalysis.cpp#L262) because `llvm.unreachable` doesn't implement `RegionBranchTerminatorOpInterface`.
The crash is caused by `DeadCodeAnalysis` assuming that `isa<RegionBranchOpInterface>(op->getParentOp())` implies `isa<RegionBranchTerminatorOpInterface>(op)` in `DeadCodeAnalysis::visit()`.
This patch tried to fix this by enabling the analysis to proceed regardless of whether `op` is a `RegionBranchTerminatorOpInterface`.
>From 8f8b644792d5e26f76d98bd8ba45440443f9a260 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 13 Oct 2023 18:16:45 -0700
Subject: [PATCH 1/2] Initial commit
---
.../mlir/Analysis/DataFlow/DeadCodeAnalysis.h | 2 +-
mlir/lib/Analysis/DataFlow/DeadCodeAnalysis.cpp | 12 +++++++-----
2 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/mlir/include/mlir/Analysis/DataFlow/DeadCodeAnalysis.h b/mlir/include/mlir/Analysis/DataFlow/DeadCodeAnalysis.h
index 7a6fea8326a58b8..ce262c3ac5291ff 100644
--- a/mlir/include/mlir/Analysis/DataFlow/DeadCodeAnalysis.h
+++ b/mlir/include/mlir/Analysis/DataFlow/DeadCodeAnalysis.h
@@ -208,7 +208,7 @@ class DeadCodeAnalysis : public DataFlowAnalysis {
/// Visit the given terminator operation that exits a region under an
/// operation with control-flow semantics. These are terminators with no CFG
/// successors.
- void visitRegionTerminator(RegionBranchTerminatorOpInterface op,
+ void visitRegionTerminator(Operation *op,
RegionBranchOpInterface branch);
/// Visit the given terminator operation that exits a callable region. These
diff --git a/mlir/lib/Analysis/DataFlow/DeadCodeAnalysis.cpp b/mlir/lib/Analysis/DataFlow/DeadCodeAnalysis.cpp
index d423d37b9770c69..30a862fa048f97a 100644
--- a/mlir/lib/Analysis/DataFlow/DeadCodeAnalysis.cpp
+++ b/mlir/lib/Analysis/DataFlow/DeadCodeAnalysis.cpp
@@ -259,8 +259,7 @@ LogicalResult DeadCodeAnalysis::visit(ProgramPoint point) {
if (isRegionOrCallableReturn(op)) {
if (auto branch = dyn_cast<RegionBranchOpInterface>(op->getParentOp())) {
// Visit the exiting terminator of a region.
- visitRegionTerminator(cast<RegionBranchTerminatorOpInterface>(op),
- branch);
+ visitRegionTerminator(op, branch);
} else if (auto callable =
dyn_cast<CallableOpInterface>(op->getParentOp())) {
// Visit the exiting terminator of a callable.
@@ -379,14 +378,17 @@ void DeadCodeAnalysis::visitRegionBranchOperation(
}
}
-void DeadCodeAnalysis::visitRegionTerminator(
- RegionBranchTerminatorOpInterface op, RegionBranchOpInterface branch) {
+void DeadCodeAnalysis::visitRegionTerminator(Operation *op,
+ RegionBranchOpInterface branch) {
std::optional<SmallVector<Attribute>> operands = getOperandValues(op);
if (!operands)
return;
SmallVector<RegionSuccessor> successors;
- op.getSuccessorRegions(*operands, successors);
+ if (auto terminator = dyn_cast<RegionBranchTerminatorOpInterface>(op))
+ terminator.getSuccessorRegions(*operands, successors);
+ else
+ branch.getSuccessorRegions(op->getParentRegion(), successors);
// Mark successor region entry blocks as executable and add this op to the
// list of predecessors.
>From ec79bc71013c8433a83948a256b313a0f93cf826 Mon Sep 17 00:00:00 2001
From: justinfargnoli <justinfargnoli at gmail.com>
Date: Fri, 13 Oct 2023 18:34:11 -0700
Subject: [PATCH 2/2] Add test
---
.../DataFlow/test-dead-code-analysis-regression.mlir | 5 +++++
1 file changed, 5 insertions(+)
create mode 100644 mlir/test/Analysis/DataFlow/test-dead-code-analysis-regression.mlir
diff --git a/mlir/test/Analysis/DataFlow/test-dead-code-analysis-regression.mlir b/mlir/test/Analysis/DataFlow/test-dead-code-analysis-regression.mlir
new file mode 100644
index 000000000000000..70c44970519cc24
--- /dev/null
+++ b/mlir/test/Analysis/DataFlow/test-dead-code-analysis-regression.mlir
@@ -0,0 +1,5 @@
+// RUN: mlir-opt -int-range-optimizations %s
+
+%0 = scf.execute_region -> tensor<5x16xi16> {
+ llvm.unreachable
+}