[Mlir-commits] [mlir] [mlir][scf] Add `no_inline` attribute to `scf.execute_region` (PR #151352)

[Jungwook Park]

https://github.com/jungpark-mlir created https://github.com/llvm/llvm-project/pull/151352

More control over the IR.
Enabling users to explicitly specify which regions should be preserved, uncovers additional opportunities to utilize `scf.execute_region` op.

>From 8c83c3dba275c7f70c2df2fda875cab5fedf5a98 Mon Sep 17 00:00:00 2001
From: Jungwook Park <jungwook.park at amd.com>
Date: Wed, 30 Jul 2025 14:52:02 +0000
Subject: [PATCH] [mlir][scf] Add `no_inline` attribute to `scf.execute_region`

More control over the IR.
Enabling users to explicitly specify which regions should be preserved, uncovers additional opportunities to utilize `scf.execute_region`.
---
 mlir/include/mlir/Dialect/SCF/IR/SCFOps.td |  4 ++++
 mlir/lib/Dialect/SCF/IR/SCF.cpp            |  2 +-
 mlir/test/Dialect/SCF/canonicalize.mlir    | 22 ++++++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/mlir/include/mlir/Dialect/SCF/IR/SCFOps.td b/mlir/include/mlir/Dialect/SCF/IR/SCFOps.td
index 2d15544e871b3..e6b83fca771a9 100644
--- a/mlir/include/mlir/Dialect/SCF/IR/SCFOps.td
+++ b/mlir/include/mlir/Dialect/SCF/IR/SCFOps.td
@@ -119,6 +119,10 @@ def ExecuteRegionOp : SCF_Op<"execute_region", [
     ```
   }];
 
+  let arguments = (ins
+    UnitAttr:$no_inline
+  );
+
   let results = (outs Variadic<AnyType>);
 
   let regions = (region AnyRegion:$region);
diff --git a/mlir/lib/Dialect/SCF/IR/SCF.cpp b/mlir/lib/Dialect/SCF/IR/SCF.cpp
index 759e58b617578..6b7f11a3469d6 100644
--- a/mlir/lib/Dialect/SCF/IR/SCF.cpp
+++ b/mlir/lib/Dialect/SCF/IR/SCF.cpp
@@ -184,7 +184,7 @@ struct SingleBlockExecuteInliner : public OpRewritePattern<ExecuteRegionOp> {
 
   LogicalResult matchAndRewrite(ExecuteRegionOp op,
                                 PatternRewriter &rewriter) const override {
-    if (!op.getRegion().hasOneBlock())
+    if (!op.getRegion().hasOneBlock() || op.getNoInline())
       return failure();
     replaceOpWithRegion(rewriter, op, op.getRegion());
     return success();
diff --git a/mlir/test/Dialect/SCF/canonicalize.mlir b/mlir/test/Dialect/SCF/canonicalize.mlir
index 12d30e17f4a8f..ae02144f06f32 100644
--- a/mlir/test/Dialect/SCF/canonicalize.mlir
+++ b/mlir/test/Dialect/SCF/canonicalize.mlir
@@ -1461,6 +1461,28 @@ func.func @execute_region_elim() {
 
 // -----
 
+// CHECK-LABEL: func @execute_region_elim_noinline
+func.func @execute_region_elim_noinline() {
+  affine.for %i = 0 to 100 {
+    "test.foo"() : () -> ()
+    %v = scf.execute_region -> i64 {
+      %x = "test.val"() : () -> i64
+      scf.yield %x : i64
+    } {no_inline}
+    "test.bar"(%v) : (i64) -> ()
+  }
+  return
+}
+
+// CHECK-NEXT:     affine.for %arg0 = 0 to 100 {
+// CHECK-NEXT:       "test.foo"() : () -> ()
+// CHECK-NEXT:       scf.execute_region
+// CHECK-NEXT:       %[[VAL:.*]] = "test.val"() : () -> i64
+// CHECK-NEXT:       scf.yield %[[VAL]] : i64
+// CHECK-NEXT:     }
+
+// -----
+
 // CHECK-LABEL: func @func_execute_region_elim
 func.func @func_execute_region_elim() {
     "test.foo"() : () -> ()