test/Sema/callingconv-sysv_abi.c

// RUN: %clang_cc1 -fsyntax-only -verify -triple x86_64-pc-linux-gnu %s

void __attribute__((ms_abi)) foo(void);
void (*pfoo)(void) = foo; // expected-error{{incompatible function pointer types}}

void __attribute__((sysv_abi)) bar(void);
void (*pbar)(void) = bar;

void (__attribute__((ms_abi)) *pbar2)(void) = bar; // expected-error{{incompatible function pointer types}}