From f25a4c9d5c856ab11fb5290fc4ac602ce441d2f5 Mon Sep 17 00:00:00 2001
From: Vimal Patel <vimal@polymagelabs.com>
Date: Mon, 26 May 2025 09:41:22 +0530
Subject: [PATCH] Fix handling of integer template argument in
 emitc.call_opaque

Integer attributes supplied to `emitc.call_opaque` as arguments were
treated as index into the operands list. This should be the case only
for the normal arguments but not for the template arguments which can't
refer to SSA values. This commit updates the handling of template
arguments in mlir-to-cpp by removing special handling of integer
attributes.
---
 mlir/lib/Target/Cpp/TranslateToCpp.cpp | 24 ++++++++++++++++--------
 mlir/test/Target/Cpp/common-cpp.mlir   |  8 ++++++++
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/mlir/lib/Target/Cpp/TranslateToCpp.cpp b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
index 0c4975a13d301..5abc112ab8c7a 100644
--- a/mlir/lib/Target/Cpp/TranslateToCpp.cpp
+++ b/mlir/lib/Target/Cpp/TranslateToCpp.cpp
@@ -692,6 +692,22 @@ static LogicalResult printOperation(CppEmitter &emitter,
     return failure();
   os << callOpaqueOp.getCallee();
 
+  // Template arguments can't refer to SSA values and as such the template
+  // arguments which are supplied in form of attributes can be emitted as is. We
+  // don't need to handle integer attributes specially like we do for arguments
+  // - see below.
+  auto emitTemplateArgs = [&](Attribute attr) -> LogicalResult {
+    return emitter.emitAttribute(op.getLoc(), attr);
+  };
+
+  if (callOpaqueOp.getTemplateArgs()) {
+    os << "<";
+    if (failed(interleaveCommaWithError(*callOpaqueOp.getTemplateArgs(), os,
+                                        emitTemplateArgs)))
+      return failure();
+    os << ">";
+  }
+
   auto emitArgs = [&](Attribute attr) -> LogicalResult {
     if (auto t = dyn_cast<IntegerAttr>(attr)) {
       // Index attributes are treated specially as operand index.
@@ -711,14 +727,6 @@ static LogicalResult printOperation(CppEmitter &emitter,
     return success();
   };
 
-  if (callOpaqueOp.getTemplateArgs()) {
-    os << "<";
-    if (failed(interleaveCommaWithError(*callOpaqueOp.getTemplateArgs(), os,
-                                        emitArgs)))
-      return failure();
-    os << ">";
-  }
-
   os << "(";
 
   LogicalResult emittedArgs =
diff --git a/mlir/test/Target/Cpp/common-cpp.mlir b/mlir/test/Target/Cpp/common-cpp.mlir
index 45fef618621cc..294e6af65bf14 100644
--- a/mlir/test/Target/Cpp/common-cpp.mlir
+++ b/mlir/test/Target/Cpp/common-cpp.mlir
@@ -109,3 +109,11 @@ func.func @apply() -> !emitc.ptr<i32> {
 func.func @array_type(%arg0: !emitc.array<3xi32>, %arg1: !emitc.array<10x20xf32>) {
   return
 }
+
+// CHECK: call_opaque_with_template_arg
+func.func @call_opaque_with_template_arg() {
+  emitc.call_opaque "init_tile"() {template_args = [512 : index]} : () -> ()
+  // CHECK-NEXT: init_tile<512>();
+  // CHECK-NEXT: return
+  return
+}