[clang] 1a1698b - [CIR] Handle NullStmt (#134889)

[via cfe-commits]

Author: Andy Kaylor
Date: 2025-04-08T13:55:12-07:00
New Revision: 1a1698b5dde28debc8331ca933a226e79164949a

URL: https://github.com/llvm/llvm-project/commit/1a1698b5dde28debc8331ca933a226e79164949a
DIFF: https://github.com/llvm/llvm-project/commit/1a1698b5dde28debc8331ca933a226e79164949a.diff

LOG: [CIR] Handle NullStmt (#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.

Added: 
    

Modified: 
    clang/lib/CIR/CodeGen/CIRGenStmt.cpp
    clang/test/CIR/CodeGen/basic.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
index 2551a670b5325..99442d2b1734e 100644
--- a/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
+++ b/clang/lib/CIR/CodeGen/CIRGenStmt.cpp
@@ -57,7 +57,14 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
     return mlir::success();
 
   switch (s->getStmtClass()) {
+  case Stmt::NoStmtClass:
+  case Stmt::CXXCatchStmtClass:
+  case Stmt::SEHExceptStmtClass:
+  case Stmt::SEHFinallyStmtClass:
+  case Stmt::MSDependentExistsStmtClass:
+    llvm_unreachable("invalid statement class to emit generically");
   case Stmt::BreakStmtClass:
+  case Stmt::NullStmtClass:
   case Stmt::CompoundStmtClass:
   case Stmt::ContinueStmtClass:
   case Stmt::DeclStmtClass:
@@ -116,12 +123,6 @@ mlir::LogicalResult CIRGenFunction::emitStmt(const Stmt *s,
     return emitOpenACCAtomicConstruct(cast<OpenACCAtomicConstruct>(*s));
   case Stmt::OMPScopeDirectiveClass:
   case Stmt::OMPErrorDirectiveClass:
-  case Stmt::NoStmtClass:
-  case Stmt::CXXCatchStmtClass:
-  case Stmt::SEHExceptStmtClass:
-  case Stmt::SEHFinallyStmtClass:
-  case Stmt::MSDependentExistsStmtClass:
-  case Stmt::NullStmtClass:
   case Stmt::LabelStmtClass:
   case Stmt::AttributedStmtClass:
   case Stmt::GotoStmtClass:
@@ -245,6 +246,11 @@ 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..7184e395ce386 100644
--- a/clang/test/CIR/CodeGen/basic.c
+++ b/clang/test/CIR/CodeGen/basic.c
@@ -90,3 +90,57 @@ 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
+
+// Verify null statement as for-loop body.
+void f5(void) {
+  for (;;)
+    ;
+}
+
+//      CIR: cir.func @f5()
+// CIR-NEXT:   cir.scope {
+// CIR-NEXT:      cir.for : cond {
+// CIR-NEXT:        %0 = cir.const #true
+// CIR-NEXT:        cir.condition(%0)
+// CIR-NEXT:      } body {
+// CIR-NEXT:        cir.yield
+// CIR-NEXT:      } step {
+// CIR-NEXT:        cir.yield
+// CIR-NEXT:      }
+// CIR-NEXT:   }
+// CIR-NEXT:   cir.return
+// CIR-NEXT: }
+
+// LLVM: define void @f5()
+// LLVM:   br label %[[SCOPE:.*]]
+// LLVM: [[SCOPE]]:
+// LLVM:   br label %[[LOOP:.*]]
+// LLVM: [[LOOP]]:
+// LLVM:   br i1 true, label %[[LOOP_STEP:.*]], label %[[LOOP_EXIT:.*]]
+// LLVM: [[LOOP_STEP]]:
+// LLVM:   br label %[[LOOP_BODY:.*]]
+// LLVM: [[LOOP_BODY]]:
+// LLVM:   br label %[[LOOP]]
+// LLVM: [[LOOP_EXIT]]:
+// LLVM:   ret void
+
+// OGCG: define{{.*}} void @f5()
+// OGCG: entry:
+// OGCG:   br label %[[LOOP:.*]]
+// OGCG: [[LOOP]]:
+// OGCG:   br label %[[LOOP]]