__attribute__((no, noclone)) signed __int128 t111_5mul(unsigned __int128 x) {
  signed __int128 r;
  if (__builtin_mul_overflow(
          x,
          (signed __int128)((-((signed __int128)(((unsigned __int128)1
                                                  << (16 * 8 - 1)) -
                                                 1)) -
                             1) /
                            2),
          &r))
    bar();
  return r;
}


x86 assembly (clang, -O0):
<t111_5mul>:
push   %rbp
mov    %rsp,%rbp
sub    $0x50,%rsp
mov    %rdi,-0x20(%rbp)
mov    %rsi,-0x18(%rbp)
mov    -0x20(%rbp),%rax
mov    -0x18(%rbp),%rcx
mov    %rcx,-0x28(%rbp)
mov    %rax,-0x30(%rbp)
mov    -0x30(%rbp),%rax
mov    -0x28(%rbp),%rcx
mov    %rcx,-0x48(%rbp)
movabs $0x4000000000000000,%rcx
mul    %rcx
mov    %rax,%rcx
mov    -0x48(%rbp),%rax
seto   %dl
test   %rax,%rax
setne  %al
or     %dl,%al
movabs $0x8000000000000000,%rsi
mov    %rcx,%rdx
sub    %rsi,%rdx
seta   %dl
or     %dl,%al
neg    %rcx
mov    %rcx,-0x38(%rbp)
movq   $0x0,-0x40(%rbp)
test   $0x1,%al
jne    118c <t111_5mul+0x7c>
jmp    1193 <t111_5mul+0x83>
mov    $0x0,%al
call   1030 <bar@plt>
mov    -0x40(%rbp),%rax
mov    -0x38(%rbp),%rcx
mov    %rcx,-0x8(%rbp)
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
mov    -0x8(%rbp),%rdx
add    $0x50,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<t111_5mul>:
push   %rbx
mov    %rdi,%rax
movabs $0x4000000000000000,%rcx
mul    %rcx
mov    %rax,%rbx
seto   %al
test   %rsi,%rsi
setne  %cl
or     %al,%cl
jne    114b <t111_5mul+0x3b>
mov    $0x1,%eax
neg    %rax
movabs $0x8000000000000000,%rax
mov    %rbx,%rcx
sbb    %rax,%rcx
jb     1152 <t111_5mul+0x42>
xor    %eax,%eax
call   1030 <bar@plt>
neg    %rbx
xor    %eax,%eax
mov    %rbx,%rdx
pop    %rbx
ret

LLVM IR (-O0):
define { i64, i64 } @t111_5mul(i64 %0, i64 %1) {
%3 = alloca i128
%4 = alloca i128
%5 = alloca i128
%6 = alloca i128
%7 = bitcast i128* %4 to { i64, i64 }*
%8 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %7, i32 0, i32 0
store i64 %0, i64* %8
%9 = getelementptr inbounds { i64, i64 }, { i64, i64 }* %7, i32 0, i32 1
store i64 %1, i64* %9
%10 = load i128, i128* %4
store i128 %10, i128* %5
%11 = load i128, i128* %5
%12 = call { i128, i1 } @llvm.umul.with.overflow.i128(i128 85070591730234615865843651857942052864, i128 %11)
%13 = extractvalue { i128, i1 } %12, 1
%14 = extractvalue { i128, i1 } %12, 0
%15 = icmp ugt i128 %14, -170141183460469231731687303715884105728
%16 = or i1 %13, %15
%17 = sub i128 0, %14
%18 = select i1 true, i128 %17, i128 %14
store i128 %18, i128* %6
br i1 %16, label %19, label %21
19: ; preds = %2
%20 = call i32 (...) @bar()
br label %21
21: ; preds = %19, %2
%22 = load i128, i128* %6
store i128 %22, i128* %3
%23 = bitcast i128* %3 to { i64, i64 }*
%24 = load { i64, i64 }, { i64, i64 }* %23
ret { i64, i64 } %24
}

LLVM IR (-O2):
define { i64, i64 } @t111_5mul(i64 %0, i64 %1) {
%3 = zext i64 %1 to i128
%4 = shl nuw i128 %3, 64
%5 = zext i64 %0 to i128
%6 = or i128 %4, %5
%7 = tail call { i128, i1 } @llvm.umul.with.overflow.i128(i128 %6, i128 85070591730234615865843651857942052864)
%8 = extractvalue { i128, i1 } %7, 1
%9 = extractvalue { i128, i1 } %7, 0
%10 = icmp ugt i128 %9, -170141183460469231731687303715884105728
%11 = or i1 %8, %10
br i1 %11, label %12, label %14
12: ; preds = %2
%13 = tail call i32 (...) @bar()
br label %14
14: ; preds = %12, %2
%15 = sub i128 0, %9
%16 = lshr exact i128 %15, 64
%17 = trunc i128 %16 to i64
%18 = insertvalue { i64, i64 } { i64 0, i64 poison }, i64 %17, 1
ret { i64, i64 } %18
}