[flang-commits] [flang] [flang] Add stack reclaim pass to reclaim allocas in loop (PR #95309)

[Tom Eccles via flang-commits]

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@@ -0,0 +1,56 @@
+//===- StackReclaim.cpp -- Insert stacksave/stackrestore in region --------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "flang/Common/Fortran.h"
+#include "flang/Optimizer/Dialect/FIRDialect.h"
+#include "flang/Optimizer/Dialect/FIROps.h"
+#include "flang/Optimizer/Transforms/Passes.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+#include "mlir/IR/Matchers.h"
+#include "mlir/Pass/Pass.h"
+
+namespace fir {
+#define GEN_PASS_DEF_STACKRECLAIM
+#include "flang/Optimizer/Transforms/Passes.h.inc"
+} // namespace fir
+
+using namespace mlir;
+
+namespace {
+
+class StackReclaimPass : public fir::impl::StackReclaimBase<StackReclaimPass> {
+public:
+  using StackReclaimBase<StackReclaimPass>::StackReclaimBase;
+
+  void runOnOperation() override;
+};
+} // namespace
+
+void StackReclaimPass::runOnOperation() {
+  auto *op = getOperation();
+  auto *context = &getContext();
+  mlir::OpBuilder builder(context);
+  mlir::Type voidPtr = mlir::LLVM::LLVMPointerType::get(context);
+
+  op->walk([&](mlir::Operation *op) {
+    if (!mlir::isa<fir::DoLoopOp>(op))
+      return;
----------------
tblah wrote:

I think you can do `op->walk([&](fir::DoLoopOp loopOp) {`

https://github.com/llvm/llvm-project/pull/95309