char *next_nonwhite_defun_arg(char ***arg_pointer) {
  char **scan = (*arg_pointer);
  char *arg = (*scan++);
  if ((arg != 0) && (*arg == ' '))
    arg = *scan++;
  if (arg == 0)
    scan -= 1;
  *arg_pointer = scan;
  return (arg == 0) ? "" : arg;
}


x86 assembly (clang, -O0):
<next_nonwhite_defun_arg>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
mov    -0x8(%rbp),%rax
mov    (%rax),%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x8,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%rax
mov    %rax,-0x18(%rbp)
cmpq   $0x0,-0x18(%rbp)
je     115a <next_nonwhite_defun_arg+0x5a>
mov    -0x18(%rbp),%rax
movsbl (%rax),%eax
cmp    $0x20,%eax
jne    115a <next_nonwhite_defun_arg+0x5a>
mov    -0x10(%rbp),%rax
mov    %rax,%rcx
add    $0x8,%rcx
mov    %rcx,-0x10(%rbp)
mov    (%rax),%rax
mov    %rax,-0x18(%rbp)
cmpq   $0x0,-0x18(%rbp)
jne    1171 <next_nonwhite_defun_arg+0x71>
mov    -0x10(%rbp),%rax
add    $0xfffffffffffffff8,%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rcx
mov    -0x8(%rbp),%rax
mov    %rcx,(%rax)
cmpq   $0x0,-0x18(%rbp)
jne    1197 <next_nonwhite_defun_arg+0x97>
lea    0xe72(%rip),%rax
mov    %rax,-0x20(%rbp)
jmp    119f <next_nonwhite_defun_arg+0x9f>
mov    -0x18(%rbp),%rax
mov    %rax,-0x20(%rbp)
mov    -0x20(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<next_nonwhite_defun_arg>:
mov    (%rdi),%rax
lea    0x8(%rax),%rcx
mov    (%rax),%rdx
test   %rdx,%rdx
je     1121 <next_nonwhite_defun_arg+0x21>
cmpb   $0x20,(%rdx)
jne    1123 <next_nonwhite_defun_arg+0x23>
mov    0x8(%rax),%rdx
add    $0x10,%rax
mov    %rax,%rcx
jmp    1123 <next_nonwhite_defun_arg+0x23>
xor    %edx,%edx
xor    %esi,%esi
test   %rdx,%rdx
lea    0xed1(%rip),%rax
cmovne %rdx,%rax
sete   %sil
shl    $0x3,%rsi
sub    %rsi,%rcx
mov    %rcx,(%rdi)
ret

LLVM IR (-O0):
@.str = [1 x i8] zeroinitializer
define i8* @next_nonwhite_defun_arg(i8*** %0) {
%2 = alloca i8***
%3 = alloca i8**
%4 = alloca i8*
store i8*** %0, i8**** %2
%5 = load i8***, i8**** %2
%6 = load i8**, i8*** %5
store i8** %6, i8*** %3
%7 = load i8**, i8*** %3
%8 = getelementptr inbounds i8*, i8** %7, i32 1
store i8** %8, i8*** %3
%9 = load i8*, i8** %7
store i8* %9, i8** %4
%10 = load i8*, i8** %4
%11 = icmp ne i8* %10, null
br i1 %11, label %12, label %21
12: ; preds = %1
%13 = load i8*, i8** %4
%14 = load i8, i8* %13
%15 = sext i8 %14 to i32
%16 = icmp eq i32 %15, 32
br i1 %16, label %17, label %21
17: ; preds = %12
%18 = load i8**, i8*** %3
%19 = getelementptr inbounds i8*, i8** %18, i32 1
store i8** %19, i8*** %3
%20 = load i8*, i8** %18
store i8* %20, i8** %4
br label %21
21: ; preds = %17, %12, %1
%22 = load i8*, i8** %4
%23 = icmp eq i8* %22, null
br i1 %23, label %24, label %27
24: ; preds = %21
%25 = load i8**, i8*** %3
%26 = getelementptr inbounds i8*, i8** %25, i64 -1
store i8** %26, i8*** %3
br label %27
27: ; preds = %24, %21
%28 = load i8**, i8*** %3
%29 = load i8***, i8**** %2
store i8** %28, i8*** %29
%30 = load i8*, i8** %4
%31 = icmp eq i8* %30, null
br i1 %31, label %32, label %33
32: ; preds = %27
br label %35
33: ; preds = %27
%34 = load i8*, i8** %4
br label %35
35: ; preds = %33, %32
%36 = phi i8* [ getelementptr inbounds ([1 x i8], [1 x i8]* @.str, i64 0, i64 0), %32 ], [ %34, %33 ]
ret i8* %36
}

LLVM IR (-O2):
@.str = [1 x i8] zeroinitializer
define i8* @next_nonwhite_defun_arg(i8*** nocapture %0) {
%2 = load i8**, i8*** %0
%3 = getelementptr inbounds i8*, i8** %2, i64 1
%4 = load i8*, i8** %2
%5 = icmp eq i8* %4, null
br i1 %5, label %12, label %6
6: ; preds = %1
%7 = load i8, i8* %4
%8 = icmp eq i8 %7, 32
br i1 %8, label %9, label %12
9: ; preds = %6
%10 = getelementptr inbounds i8*, i8** %2, i64 2
%11 = load i8*, i8** %3
br label %12
12: ; preds = %9, %6, %1
%13 = phi i8** [ %10, %9 ], [ %3, %6 ], [ %3, %1 ]
%14 = phi i8* [ %11, %9 ], [ %4, %6 ], [ null, %1 ]
%15 = icmp eq i8* %14, null
%16 = select i1 %15, i8* getelementptr inbounds ([1 x i8], [1 x i8]* @.str, i64 0, i64 0), i8* %14
%17 = sext i1 %15 to i64
%18 = getelementptr i8*, i8** %13, i64 %17
store i8** %18, i8*** %0
ret i8* %16
}