[mlir][func] Add eliminate-function-parameter pass #160654
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@llvm/pr-subscribers-mlir Author: lonely eagle (linuxlonelyeagle) ChangesAdded the eliminate-function-parameter pass. During the IR transformation process, function parameters may become unused, and this pass is used to remove unused parameters in functions. Full diff: https://github.com/llvm/llvm-project/pull/160654.diff 5 Files Affected:
diff --git a/mlir/include/mlir/Dialect/Func/Transforms/Passes.h b/mlir/include/mlir/Dialect/Func/Transforms/Passes.h
index 6fe9cc4bb2986..1369a3627d0f2 100644
--- a/mlir/include/mlir/Dialect/Func/Transforms/Passes.h
+++ b/mlir/include/mlir/Dialect/Func/Transforms/Passes.h
@@ -22,7 +22,7 @@ class RewritePatternSet;
namespace func {
-#define GEN_PASS_DECL_DUPLICATEFUNCTIONELIMINATIONPASS
+#define GEN_PASS_DECL
#include "mlir/Dialect/Func/Transforms/Passes.h.inc"
//===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/Dialect/Func/Transforms/Passes.td b/mlir/include/mlir/Dialect/Func/Transforms/Passes.td
index 4163997515bb0..0e57bc3e0da91 100644
--- a/mlir/include/mlir/Dialect/Func/Transforms/Passes.td
+++ b/mlir/include/mlir/Dialect/Func/Transforms/Passes.td
@@ -21,4 +21,12 @@ def DuplicateFunctionEliminationPass : Pass<"duplicate-function-elimination",
}];
}
+def EliminateFunctionParameterPass : Pass<"eliminate-function-parameter",
+ "ModuleOp"> {
+ let summary = "Eliminate function parameter";
+ let description = [{
+ Eliminate function parameter is used to remove unnecessary parameters passed
+ to a function, then update the function call.
+ }];
+}
#endif // MLIR_DIALECT_FUNC_TRANSFORMS_PASSES_TD
diff --git a/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt b/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt
index 0bed59e109503..3553613543c86 100644
--- a/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt
+++ b/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt
@@ -1,4 +1,5 @@
add_mlir_dialect_library(MLIRFuncTransforms
+ EliminateFunctionParameter.cpp
DuplicateFunctionElimination.cpp
FuncConversions.cpp
diff --git a/mlir/lib/Dialect/Func/Transforms/EliminateFunctionParameter.cpp b/mlir/lib/Dialect/Func/Transforms/EliminateFunctionParameter.cpp
new file mode 100644
index 0000000000000..c5412e117878b
--- /dev/null
+++ b/mlir/lib/Dialect/Func/Transforms/EliminateFunctionParameter.cpp
@@ -0,0 +1,88 @@
+//===- EliminateFunctionParameter.cpp.cpp - Eliminate function Parameter --===//
+//
+// 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 "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Dialect/Func/Transforms/Passes.h"
+
+namespace mlir {
+namespace func {
+#define GEN_PASS_DEF_ELIMINATEFUNCTIONPARAMETERPASS
+#include "mlir/Dialect/Func/Transforms/Passes.h.inc"
+} // namespace func
+
+/// This function eliminates unnecessary parameters within the function.
+static LogicalResult updateFunc(func::FuncOp funcOp, BitVector &arguemntNoUse) {
+ Block &entryBlock = funcOp.front();
+ bool change = false;
+ FunctionType origType = funcOp.getFunctionType();
+ llvm::ArrayRef<Type> origInputTypes = origType.getInputs();
+ SmallVector<Type, 4> newInputTypes;
+ for (auto iter : llvm::enumerate(funcOp.getArguments())) {
+ size_t position = iter.index();
+ if (!iter.value().use_empty()) {
+ newInputTypes.push_back(origInputTypes[position]);
+ continue;
+ }
+ arguemntNoUse.set(position);
+ entryBlock.eraseArgument(position);
+ change = true;
+ }
+
+ if (change) {
+ auto newFunctionType = FunctionType::get(funcOp.getContext(), newInputTypes,
+ origType.getResults());
+ funcOp.setFunctionType(newFunctionType);
+ }
+ return success(change);
+}
+
+/// After eliminating redundant parameters from the function, update the
+/// function calls.
+static LogicalResult updateCall(func::CallOp callOp,
+ BitVector &argumentsNoUse) {
+ ValueRange origOperands = callOp.getOperands();
+ SmallVector<Value, 4> newOperands;
+ for (auto iter : llvm::enumerate(origOperands)) {
+ if (!argumentsNoUse[iter.index()])
+ newOperands.push_back(iter.value());
+ }
+ callOp->setOperands(newOperands);
+ return success();
+}
+
+namespace {
+struct EliminateFunctionParameterPass
+ : public func::impl::EliminateFunctionParameterPassBase<
+ EliminateFunctionParameterPass> {
+ using EliminateFunctionParameterPassBase<
+ EliminateFunctionParameterPass>::EliminateFunctionParameterPassBase;
+ void runOnOperation() override {
+ ModuleOp moduleOp = getOperation();
+ for (auto funcOp : moduleOp.getOps<func::FuncOp>()) {
+ size_t argumentSize = funcOp.getArguments().size();
+ if (!argumentSize)
+ continue;
+ BitVector argumentNoUse(argumentSize);
+ if (failed(updateFunc(funcOp, argumentNoUse)))
+ continue;
+
+ auto symbolOp = mlir::cast<SymbolOpInterface>(funcOp.getOperation());
+ auto users = symbolOp.getSymbolUses(moduleOp);
+
+ if (!users.has_value())
+ continue;
+ for (SymbolTable::SymbolUse user : *users) {
+ Operation *call = user.getUser();
+ (void)updateCall(mlir::cast<func::CallOp>(call), argumentNoUse);
+ }
+ }
+ }
+};
+
+} // namespace
+} // namespace mlir
diff --git a/mlir/test/Dialect/Func/eliminate-function-parameter.mlir b/mlir/test/Dialect/Func/eliminate-function-parameter.mlir
new file mode 100644
index 0000000000000..0bd35ec6bd1c7
--- /dev/null
+++ b/mlir/test/Dialect/Func/eliminate-function-parameter.mlir
@@ -0,0 +1,32 @@
+// RUN: mlir-opt %s --split-input-file --eliminate-function-parameter | \
+// RUN: FileCheck %s
+
+func.func @single_parameter(%arg: index) {
+ return
+}
+
+func.func @mutl_parameter(%arg0 : index, %arg1 : index) -> index {
+ return %arg0 : index
+}
+
+func.func @eliminate_parameter(%arg0: index, %arg1: index) -> index {
+ func.call @single_parameter(%arg0) : (index) -> ()
+ %ret = func.call @mutl_parameter(%arg0, %arg0) : (index, index) -> (index)
+ return %ret : index
+}
+
+// CHECK-LABEL: func @single_parameter() {
+// CHECK: return
+// CHECK: }
+
+// CHECK-LABEL: func @mutl_parameter(
+// CHECK-SAME: %[[ARG0:.*]]: index) -> index {
+// CHECK: return %[[ARG0]] : index
+// CHECK: }
+
+// CHECK-LABEL: func @eliminate_parameter(
+// CHECK-SAME: %[[ARG0:.*]]: index) -> index {
+// CHECK: call @single_parameter() : () -> ()
+// CHECK: %[[RET:.*]] = call @mutl_parameter(%[[ARG0]]) : (index) -> index
+// CHECK: return %[[RET]] : index
+// CHECK: }
|
|
@llvm/pr-subscribers-mlir-func Author: lonely eagle (linuxlonelyeagle) ChangesAdded the eliminate-function-parameter pass. During the IR transformation process, function parameters may become unused, and this pass is used to remove unused parameters in functions. Full diff: https://github.com/llvm/llvm-project/pull/160654.diff 5 Files Affected:
diff --git a/mlir/include/mlir/Dialect/Func/Transforms/Passes.h b/mlir/include/mlir/Dialect/Func/Transforms/Passes.h
index 6fe9cc4bb2986..1369a3627d0f2 100644
--- a/mlir/include/mlir/Dialect/Func/Transforms/Passes.h
+++ b/mlir/include/mlir/Dialect/Func/Transforms/Passes.h
@@ -22,7 +22,7 @@ class RewritePatternSet;
namespace func {
-#define GEN_PASS_DECL_DUPLICATEFUNCTIONELIMINATIONPASS
+#define GEN_PASS_DECL
#include "mlir/Dialect/Func/Transforms/Passes.h.inc"
//===----------------------------------------------------------------------===//
diff --git a/mlir/include/mlir/Dialect/Func/Transforms/Passes.td b/mlir/include/mlir/Dialect/Func/Transforms/Passes.td
index 4163997515bb0..0e57bc3e0da91 100644
--- a/mlir/include/mlir/Dialect/Func/Transforms/Passes.td
+++ b/mlir/include/mlir/Dialect/Func/Transforms/Passes.td
@@ -21,4 +21,12 @@ def DuplicateFunctionEliminationPass : Pass<"duplicate-function-elimination",
}];
}
+def EliminateFunctionParameterPass : Pass<"eliminate-function-parameter",
+ "ModuleOp"> {
+ let summary = "Eliminate function parameter";
+ let description = [{
+ Eliminate function parameter is used to remove unnecessary parameters passed
+ to a function, then update the function call.
+ }];
+}
#endif // MLIR_DIALECT_FUNC_TRANSFORMS_PASSES_TD
diff --git a/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt b/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt
index 0bed59e109503..3553613543c86 100644
--- a/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt
+++ b/mlir/lib/Dialect/Func/Transforms/CMakeLists.txt
@@ -1,4 +1,5 @@
add_mlir_dialect_library(MLIRFuncTransforms
+ EliminateFunctionParameter.cpp
DuplicateFunctionElimination.cpp
FuncConversions.cpp
diff --git a/mlir/lib/Dialect/Func/Transforms/EliminateFunctionParameter.cpp b/mlir/lib/Dialect/Func/Transforms/EliminateFunctionParameter.cpp
new file mode 100644
index 0000000000000..c5412e117878b
--- /dev/null
+++ b/mlir/lib/Dialect/Func/Transforms/EliminateFunctionParameter.cpp
@@ -0,0 +1,88 @@
+//===- EliminateFunctionParameter.cpp.cpp - Eliminate function Parameter --===//
+//
+// 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 "mlir/Dialect/Func/IR/FuncOps.h"
+#include "mlir/Dialect/Func/Transforms/Passes.h"
+
+namespace mlir {
+namespace func {
+#define GEN_PASS_DEF_ELIMINATEFUNCTIONPARAMETERPASS
+#include "mlir/Dialect/Func/Transforms/Passes.h.inc"
+} // namespace func
+
+/// This function eliminates unnecessary parameters within the function.
+static LogicalResult updateFunc(func::FuncOp funcOp, BitVector &arguemntNoUse) {
+ Block &entryBlock = funcOp.front();
+ bool change = false;
+ FunctionType origType = funcOp.getFunctionType();
+ llvm::ArrayRef<Type> origInputTypes = origType.getInputs();
+ SmallVector<Type, 4> newInputTypes;
+ for (auto iter : llvm::enumerate(funcOp.getArguments())) {
+ size_t position = iter.index();
+ if (!iter.value().use_empty()) {
+ newInputTypes.push_back(origInputTypes[position]);
+ continue;
+ }
+ arguemntNoUse.set(position);
+ entryBlock.eraseArgument(position);
+ change = true;
+ }
+
+ if (change) {
+ auto newFunctionType = FunctionType::get(funcOp.getContext(), newInputTypes,
+ origType.getResults());
+ funcOp.setFunctionType(newFunctionType);
+ }
+ return success(change);
+}
+
+/// After eliminating redundant parameters from the function, update the
+/// function calls.
+static LogicalResult updateCall(func::CallOp callOp,
+ BitVector &argumentsNoUse) {
+ ValueRange origOperands = callOp.getOperands();
+ SmallVector<Value, 4> newOperands;
+ for (auto iter : llvm::enumerate(origOperands)) {
+ if (!argumentsNoUse[iter.index()])
+ newOperands.push_back(iter.value());
+ }
+ callOp->setOperands(newOperands);
+ return success();
+}
+
+namespace {
+struct EliminateFunctionParameterPass
+ : public func::impl::EliminateFunctionParameterPassBase<
+ EliminateFunctionParameterPass> {
+ using EliminateFunctionParameterPassBase<
+ EliminateFunctionParameterPass>::EliminateFunctionParameterPassBase;
+ void runOnOperation() override {
+ ModuleOp moduleOp = getOperation();
+ for (auto funcOp : moduleOp.getOps<func::FuncOp>()) {
+ size_t argumentSize = funcOp.getArguments().size();
+ if (!argumentSize)
+ continue;
+ BitVector argumentNoUse(argumentSize);
+ if (failed(updateFunc(funcOp, argumentNoUse)))
+ continue;
+
+ auto symbolOp = mlir::cast<SymbolOpInterface>(funcOp.getOperation());
+ auto users = symbolOp.getSymbolUses(moduleOp);
+
+ if (!users.has_value())
+ continue;
+ for (SymbolTable::SymbolUse user : *users) {
+ Operation *call = user.getUser();
+ (void)updateCall(mlir::cast<func::CallOp>(call), argumentNoUse);
+ }
+ }
+ }
+};
+
+} // namespace
+} // namespace mlir
diff --git a/mlir/test/Dialect/Func/eliminate-function-parameter.mlir b/mlir/test/Dialect/Func/eliminate-function-parameter.mlir
new file mode 100644
index 0000000000000..0bd35ec6bd1c7
--- /dev/null
+++ b/mlir/test/Dialect/Func/eliminate-function-parameter.mlir
@@ -0,0 +1,32 @@
+// RUN: mlir-opt %s --split-input-file --eliminate-function-parameter | \
+// RUN: FileCheck %s
+
+func.func @single_parameter(%arg: index) {
+ return
+}
+
+func.func @mutl_parameter(%arg0 : index, %arg1 : index) -> index {
+ return %arg0 : index
+}
+
+func.func @eliminate_parameter(%arg0: index, %arg1: index) -> index {
+ func.call @single_parameter(%arg0) : (index) -> ()
+ %ret = func.call @mutl_parameter(%arg0, %arg0) : (index, index) -> (index)
+ return %ret : index
+}
+
+// CHECK-LABEL: func @single_parameter() {
+// CHECK: return
+// CHECK: }
+
+// CHECK-LABEL: func @mutl_parameter(
+// CHECK-SAME: %[[ARG0:.*]]: index) -> index {
+// CHECK: return %[[ARG0]] : index
+// CHECK: }
+
+// CHECK-LABEL: func @eliminate_parameter(
+// CHECK-SAME: %[[ARG0:.*]]: index) -> index {
+// CHECK: call @single_parameter() : () -> ()
+// CHECK: %[[RET:.*]] = call @mutl_parameter(%[[ARG0]]) : (index) -> index
+// CHECK: return %[[RET]] : index
+// CHECK: }
|
linuxlonelyeagle
requested review from
ftynse,
joker-eph,
krzysz00,
rengolin and
bondhugula
|
Isn't "remove-dead-values" already doing this? |
joker-eph
reviewed
Sep 25, 2025
| func.call @single_parameter(%arg0) : (index) -> () | ||
| %ret = func.call @mutl_parameter(%arg0, %arg0) : (index, index) -> (index) | ||
| return %ret : index | ||
| } |
There was a problem hiding this comment.
Note: all these functions are public, it is incorrect to change the signature of a public function: you can't know about call sites outside of the current module.
There was a problem hiding this comment.
This is something I hadn't considered.Thank you for the reminder. It has helped me better understand the meaning of “public function.”
After reviewing the definition of |
It appears that remove-dead-values does not work for this. run pass |
|
I've reopened this PR. Maybe we should discuss it. |
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Added the eliminate-function-parameter pass. During the IR transformation process, function parameters may become unused, and this pass is used to remove unused parameters in functions.