https://github.com/kumarak updated https://github.com/llvm/llvm-project/pull/208741
>From b20cd8e7c8a8d2d0038c476f8ec2660398b7b466 Mon Sep 17 00:00:00 2001 From: AkshayK <[email protected]> Date: Fri, 10 Jul 2026 10:30:16 -0400 Subject: [PATCH] [CIR] Handle __builtin_c23_va_start C23 va_start expands to __builtin_c23_va_start, which was hitting the unimplemented-builtin NYI path, so all variadic code failed to compile with -fclangir in -std=c23 mode. Lower it exactly like __builtin_va_start: the va_list is always arg 0. --- clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp | 1 + clang/test/CIR/CodeGen/var_arg-c23.c | 41 +++++++++++++++++++++++++ 2 files changed, 42 insertions(+) create mode 100644 clang/test/CIR/CodeGen/var_arg-c23.c diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp index 3c48b8b67d9ee..84bb33663de05 100644 --- a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp +++ b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp @@ -1059,6 +1059,7 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID, // C stdarg builtins. case Builtin::BI__builtin_stdarg_start: case Builtin::BI__builtin_va_start: + case Builtin::BI__builtin_c23_va_start: case Builtin::BI__va_start: { mlir::Value vaList = builtinID == Builtin::BI__va_start ? emitScalarExpr(e->getArg(0)) diff --git a/clang/test/CIR/CodeGen/var_arg-c23.c b/clang/test/CIR/CodeGen/var_arg-c23.c new file mode 100644 index 0000000000000..1bb0b7099b5fe --- /dev/null +++ b/clang/test/CIR/CodeGen/var_arg-c23.c @@ -0,0 +1,41 @@ +// RUN: %clang_cc1 -std=c23 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-cir %s -o %t.cir +// RUN: FileCheck --input-file=%t.cir %s -check-prefix=CIR +// RUN: %clang_cc1 -std=c23 -triple x86_64-unknown-linux-gnu -Wno-unused-value -fclangir -emit-llvm %s -o %t-cir.ll +// RUN: FileCheck --input-file=%t-cir.ll %s -check-prefix=LLVM +// RUN: %clang_cc1 -std=c23 -triple x86_64-unknown-linux-gnu -Wno-unused-value -emit-llvm %s -o %t.ll +// RUN: FileCheck --input-file=%t.ll %s -check-prefix=LLVM + +void noargs(...) { + __builtin_va_list list; + __builtin_va_start(list, 0); + __builtin_c23_va_start(list); + __builtin_va_end(list); +} + +// CIR-LABEL: cir.func {{.*}} @noargs( +// CIR: %[[VAAREA:.+]] = cir.alloca "list" {{.*}} : !cir.ptr<!cir.array<!rec___va_list_tag x 1>> +// CIR: %[[VA_PTR0:.+]] = cir.cast array_to_ptrdecay %[[VAAREA]] +// CIR-NEXT: cir.va_start %[[VA_PTR0]] : !cir.ptr<!rec___va_list_tag> +// CIR: %[[VA_PTR1:.+]] = cir.cast array_to_ptrdecay %[[VAAREA]] +// CIR-NEXT: cir.va_start %[[VA_PTR1]] : !cir.ptr<!rec___va_list_tag> +// CIR: cir.va_end %{{.+}} : !cir.ptr<!rec___va_list_tag> + +// LLVM-LABEL: define {{.*}}void @noargs(...) +// LLVM: %[[VAAREA:.+]] = alloca [1 x %struct.__va_list_tag] +// LLVM: call void @llvm.va_start.p0(ptr %{{.+}}) +// LLVM: call void @llvm.va_start.p0(ptr %{{.+}}) +// LLVM: call void @llvm.va_end.p0(ptr %{{.+}}) + +void with_param(int count, ...) { + __builtin_va_list list; + __builtin_c23_va_start(list, count); + __builtin_va_end(list); +} + +// CIR-LABEL: cir.func {{.*}} @with_param( +// CIR: cir.va_start %{{.+}} : !cir.ptr<!rec___va_list_tag> +// CIR: cir.va_end %{{.+}} : !cir.ptr<!rec___va_list_tag> + +// LLVM-LABEL: define {{.*}}void @with_param(i32 noundef %{{.+}}, ...) +// LLVM: call void @llvm.va_start.p0(ptr %{{.+}}) +// LLVM: call void @llvm.va_end.p0(ptr %{{.+}}) _______________________________________________ cfe-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
