[flang-commits] [flang] [flang][NFC] use tablegen to create StackArrays constructor (PR #90038)

[Tom Eccles via flang-commits]

https://github.com/tblah updated https://github.com/llvm/llvm-project/pull/90038

>From 6efef1d6993035826ad7ccae93b1558d8dd7ed88 Mon Sep 17 00:00:00 2001
From: Tom Eccles <tom.eccles at arm.com>
Date: Thu, 25 Apr 2024 09:51:51 +0000
Subject: [PATCH] [flang][NFC] use tablegen to create StackArrays constructor

Stack arrays needs to stay running only on func.func because it needs
to know which block terminators can end the function (rather than just
branch between unstructured control flow). A similar concept does not
exist at the more abstract level of "any top level mlir operation".

For example, it currently looks for func::ReturnOp and
fir::UnreachableOp as points when execution can end. If this were to be
run on omp.declare_reduction, it would also need to understand
omp.YieldOp (perhaps only when omp.declare_reduction is the parent).
There isn't a generic concept in MLIR for this.
---
 flang/include/flang/Optimizer/Transforms/Passes.h  | 2 +-
 flang/include/flang/Optimizer/Transforms/Passes.td | 1 -
 flang/include/flang/Tools/CLOptions.inc            | 2 +-
 flang/lib/Optimizer/Transforms/StackArrays.cpp     | 4 ----
 4 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/flang/include/flang/Optimizer/Transforms/Passes.h b/flang/include/flang/Optimizer/Transforms/Passes.h
index fd7a4a3883c996..76396ac96eecb1 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.h
+++ b/flang/include/flang/Optimizer/Transforms/Passes.h
@@ -47,6 +47,7 @@ namespace fir {
 #define GEN_PASS_DECL_POLYMORPHICOPCONVERSION
 #define GEN_PASS_DECL_OPENACCDATAOPERANDCONVERSION
 #define GEN_PASS_DECL_ADDDEBUGINFO
+#define GEN_PASS_DECL_STACKARRAYS
 #include "flang/Optimizer/Transforms/Passes.h.inc"
 
 std::unique_ptr<mlir::Pass> createAffineDemotionPass();
@@ -58,7 +59,6 @@ createExternalNameConversionPass(bool appendUnderscore);
 std::unique_ptr<mlir::Pass> createMemDataFlowOptPass();
 std::unique_ptr<mlir::Pass> createPromoteToAffinePass();
 std::unique_ptr<mlir::Pass> createMemoryAllocationPass();
-std::unique_ptr<mlir::Pass> createStackArraysPass();
 std::unique_ptr<mlir::Pass> createAliasTagsPass();
 std::unique_ptr<mlir::Pass>
 createAddDebugInfoPass(fir::AddDebugInfoOptions options = {});
diff --git a/flang/include/flang/Optimizer/Transforms/Passes.td b/flang/include/flang/Optimizer/Transforms/Passes.td
index c3d5c336af40ba..0b2d274ee74348 100644
--- a/flang/include/flang/Optimizer/Transforms/Passes.td
+++ b/flang/include/flang/Optimizer/Transforms/Passes.td
@@ -257,7 +257,6 @@ def StackArrays : Pass<"stack-arrays", "mlir::ModuleOp"> {
     allocations.
   }];
   let dependentDialects = [ "fir::FIROpsDialect" ];
-  let constructor = "::fir::createStackArraysPass()";
 }
 
 def AddAliasTags : Pass<"fir-add-alias-tags", "mlir::ModuleOp"> {
diff --git a/flang/include/flang/Tools/CLOptions.inc b/flang/include/flang/Tools/CLOptions.inc
index f24716333d9acf..aaee1f67567e52 100644
--- a/flang/include/flang/Tools/CLOptions.inc
+++ b/flang/include/flang/Tools/CLOptions.inc
@@ -258,7 +258,7 @@ inline void createDefaultFIROptimizerPassPipeline(
   pm.addPass(mlir::createCSEPass());
 
   if (pc.StackArrays)
-    pm.addPass(fir::createStackArraysPass());
+    pm.addPass(fir::createStackArrays());
   else
     fir::addMemoryAllocationOpt(pm);
 
diff --git a/flang/lib/Optimizer/Transforms/StackArrays.cpp b/flang/lib/Optimizer/Transforms/StackArrays.cpp
index 1c213abefe6f5f..c81524dd16a77e 100644
--- a/flang/lib/Optimizer/Transforms/StackArrays.cpp
+++ b/flang/lib/Optimizer/Transforms/StackArrays.cpp
@@ -776,7 +776,3 @@ void StackArraysPass::runOnFunc(mlir::Operation *func) {
     signalPassFailure();
   }
 }
-
-std::unique_ptr<mlir::Pass> fir::createStackArraysPass() {
-  return std::make_unique<StackArraysPass>();
-}