Clang requires explicit size suffixes for potentially ambiguous instructions: x86/realmode.c:1647:2: error: ambiguous instructions require an explicit suffix (could be 'cmpb', 'cmpw', or 'cmpl') MK_INSN_PERF(perf_memory_load, "cmp $0, (%edi)"); ^ x86/realmode.c:1591:10: note: expanded from macro 'MK_INSN_PERF' "1:" insn "\n" \ ^ <inline asm>:8:3: note: instantiated into assembly here 1:cmp $0, (%edi) ^ The 'w' and 'l' suffixes generate code that's identical to the gcc version without them. Signed-off-by: Bill Wendling <morbo@xxxxxxxxxx> --- x86/realmode.c | 6 +++--- x86/syscall.c | 2 +- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/x86/realmode.c b/x86/realmode.c index f5967ef..31f84d0 100644 --- a/x86/realmode.c +++ b/x86/realmode.c @@ -1644,7 +1644,7 @@ static void test_perf_memory_load(void) { u32 cyc, tmp; - MK_INSN_PERF(perf_memory_load, "cmp $0, (%edi)"); + MK_INSN_PERF(perf_memory_load, "cmpw $0, (%edi)"); init_inregs(&(struct regs){ .edi = (u32)&tmp }); @@ -1657,7 +1657,7 @@ static void test_perf_memory_store(void) { u32 cyc, tmp; - MK_INSN_PERF(perf_memory_store, "mov %ax, (%edi)"); + MK_INSN_PERF(perf_memory_store, "movw %ax, (%edi)"); init_inregs(&(struct regs){ .edi = (u32)&tmp }); @@ -1670,7 +1670,7 @@ static void test_perf_memory_rmw(void) { u32 cyc, tmp; - MK_INSN_PERF(perf_memory_rmw, "add $1, (%edi)"); + MK_INSN_PERF(perf_memory_rmw, "addw $1, (%edi)"); init_inregs(&(struct regs){ .edi = (u32)&tmp }); diff --git a/x86/syscall.c b/x86/syscall.c index b4f5ac0..b7e29d6 100644 --- a/x86/syscall.c +++ b/x86/syscall.c @@ -38,7 +38,7 @@ static void handle_db(struct ex_regs *regs) /* expects desired ring 3 flags in rax */ asm("syscall32_target:\n" - " cmp $0, code_segment_upon_db(%rip)\n" + " cmpl $0, code_segment_upon_db(%rip)\n" " jne back_to_test\n" " mov %eax,%r11d\n" " sysretl\n"); -- 2.25.0.265.gbab2e86ba0-goog