[clang] [CIR] Handle NullStmt (PR #134889)

[Andy Kaylor via cfe-commits]

https://github.com/andykaylor created https://github.com/llvm/llvm-project/pull/134889

The handling for NullStmt was going to an error saying the statement handling wasn't implemented. It doesn't need any implementation. It is sufficient for emitSimpleStmt to just return success for that statement class. This change does that.

>From efbec15d42a83cd2f4980418a939a88af7c7b92a Mon Sep 17 00:00:00 2001
From: Andy Kaylor <akaylor at nvidia.com>
Date: Tue, 8 Apr 2025 10:01:21 -0700
Subject: [PATCH] [CIR] Handle NullStmt

The handling for NullStmt was going to an error saying the statement
handling wasn't implemented. It doesn't need any implementation. It is
sufficient for emitSimpleStmt to just return success for that statement
class. This change does that.
---
 clang/lib/CIR/CodeGen/CIRGenStmt.cpp |  7 ++++++-
 clang/test/CIR/CodeGen/basic.c       | 15 +++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index 00d33e7feddff..072370ffeb4c8 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -57,6 +57,7 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
 
   switch (s->getStmtClass()) {
   case Stmt::BreakStmtClass:
+  case Stmt::NullStmtClass:
   case Stmt::CompoundStmtClass:
   case Stmt::ContinueStmtClass:
   case Stmt::DeclStmtClass:
@@ -93,7 +94,6 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
   case Stmt::SEHExceptStmtClass:
   case Stmt::SEHFinallyStmtClass:
   case Stmt::MSDependentExistsStmtClass:
-  case Stmt::NullStmtClass:
   case Stmt::LabelStmtClass:
   case Stmt::AttributedStmtClass:
   case Stmt::GotoStmtClass:
@@ -231,6 +231,11 @@ mlir::LogicalResult CIRGenFunction::emitSimpleStmt(const Stmt *s,
     break;
   case Stmt::ContinueStmtClass:
     return emitContinueStmt(cast<ContinueStmt>(*s));
+
+  // NullStmt doesn't need any handling, but we need to say we handled it.
+  case Stmt::NullStmtClass:
+    break;
+
   case Stmt::BreakStmtClass:
     return emitBreakStmt(cast<BreakStmt>(*s));
   case Stmt::ReturnStmtClass:
diff --git a/clang/test/CIR/CodeGen/basic.c b/clang/test/CIR/CodeGen/basic.c
index 673ff256c22af..6365dc2158138 100644
--- a/clang/test/CIR/CodeGen/basic.c
+++ b/clang/test/CIR/CodeGen/basic.c
@@ -90,3 +90,18 @@ int f3(void) {
 // OGCG-NEXT:   store i32 3, ptr %[[I_PTR]], align 4
 // OGCG-NEXT:   %[[I:.*]] = load i32, ptr %[[I_PTR]], align 4
 // OGCG-NEXT:   ret i32 %[[I]]
+
+// Verify null statement handling.
+void f4(void) {
+  ;
+}
+
+//      CIR: cir.func @f4()
+// CIR-NEXT:   cir.return
+
+//      LLVM: define void @f4()
+// LLVM-NEXT:   ret void
+
+//      OGCG: define{{.*}} void @f4()
+// OGCG-NEXT: entry:
+// OGCG-NEXT:   ret void