heir1(lval) int lval[];
{
  int k, lval2[2];
  k = heir2(lval);
  if (match("=")) {
    if (k == 0) {
      needlval();
      return 0;
    }
    if (lval[1])
      mnem_push();
    if (heir1(lval2))
      rvalue(lval2);
    store(lval);
    return 0;
  } else
    return k;
}


x86 assembly (clang, -O0):
<heir1>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
mov    -0x10(%rbp),%rdi
mov    $0x0,%al
call   1090 <heir2@plt>
mov    %eax,-0x14(%rbp)
lea    0xe6f(%rip),%rdi
mov    $0x0,%al
call   1070 <match@plt>
cmp    $0x0,%eax
je     1207 <heir1+0x97>
cmpl   $0x0,-0x14(%rbp)
jne    11be <heir1+0x4e>
mov    $0x0,%al
call   1080 <needlval@plt>
movl   $0x0,-0x4(%rbp)
jmp    120d <heir1+0x9d>
mov    -0x10(%rbp),%rax
cmpl   $0x0,0x4(%rax)
je     11d3 <heir1+0x63>
mov    $0x0,%al
call   1030 <mnem_push@plt>
lea    -0x1c(%rbp),%rdi
call   1060 <heir1@plt>
cmp    $0x0,%eax
je     11f0 <heir1+0x80>
lea    -0x1c(%rbp),%rdi
mov    $0x0,%al
call   1050 <rvalue@plt>
mov    -0x10(%rbp),%rdi
mov    $0x0,%al
call   1040 <store@plt>
movl   $0x0,-0x4(%rbp)
jmp    120d <heir1+0x9d>
mov    -0x14(%rbp),%eax
mov    %eax,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<heir1>:
push   %rbp
push   %rbx
push   %rax
mov    %rdi,%rbx
xor    %eax,%eax
call   1090 <heir2@plt>
mov    %eax,%ebp
lea    0xe7a(%rip),%rdi
xor    %eax,%eax
call   1070 <match@plt>
test   %eax,%eax
je     11cf <heir1+0x5f>
test   %ebp,%ebp
je     11c6 <heir1+0x56>
cmpl   $0x0,0x4(%rbx)
je     11a2 <heir1+0x32>
xor    %eax,%eax
call   1030 <mnem_push@plt>
mov    %rsp,%rdi
call   1060 <heir1@plt>
test   %eax,%eax
je     11b8 <heir1+0x48>
mov    %rsp,%rdi
xor    %eax,%eax
call   1050 <rvalue@plt>
xor    %ebp,%ebp
mov    %rbx,%rdi
xor    %eax,%eax
call   1040 <store@plt>
jmp    11cf <heir1+0x5f>
xor    %ebp,%ebp
xor    %eax,%eax
call   1080 <needlval@plt>
mov    %ebp,%eax
add    $0x8,%rsp
pop    %rbx
pop    %rbp
ret

LLVM IR (-O0):
@.str = [2 x i8] c"=\00"
define i32 @heir1(i32* %0) {
%2 = alloca i32
%3 = alloca i32*
%4 = alloca i32
%5 = alloca [2 x i32]
store i32* %0, i32** %3
%6 = load i32*, i32** %3
%7 = call i32 (i32*, ...) bitcast (i32 (...)* @heir2 to i32 (i32*, ...)*)(i32* %6)
store i32 %7, i32* %4
%8 = call i32 (i8*, ...) bitcast (i32 (...)* @match to i32 (i8*, ...)*)(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
%9 = icmp ne i32 %8, 0
br i1 %9, label %10, label %32
10: ; preds = %1
%11 = load i32, i32* %4
%12 = icmp eq i32 %11, 0
br i1 %12, label %13, label %15
13: ; preds = %10
%14 = call i32 (...) @needlval()
store i32 0, i32* %2
br label %34
15: ; preds = %10
%16 = load i32*, i32** %3
%17 = getelementptr inbounds i32, i32* %16, i64 1
%18 = load i32, i32* %17
%19 = icmp ne i32 %18, 0
br i1 %19, label %20, label %22
20: ; preds = %15
%21 = call i32 (...) @mnem_push()
br label %22
22: ; preds = %20, %15
%23 = getelementptr inbounds [2 x i32], [2 x i32]* %5, i64 0, i64 0
%24 = call i32 @heir1(i32* %23)
%25 = icmp ne i32 %24, 0
br i1 %25, label %26, label %29
26: ; preds = %22
%27 = getelementptr inbounds [2 x i32], [2 x i32]* %5, i64 0, i64 0
%28 = call i32 (i32*, ...) bitcast (i32 (...)* @rvalue to i32 (i32*, ...)*)(i32* %27)
br label %29
29: ; preds = %26, %22
%30 = load i32*, i32** %3
%31 = call i32 (i32*, ...) bitcast (i32 (...)* @store to i32 (i32*, ...)*)(i32* %30)
store i32 0, i32* %2
br label %34
32: ; preds = %1
%33 = load i32, i32* %4
store i32 %33, i32* %2
br label %34
34: ; preds = %32, %29, %13
%35 = load i32, i32* %2
ret i32 %35
}

LLVM IR (-O2):
@.str = [2 x i8] c"=\00"
define i32 @heir1(i32* %0) {
%2 = alloca [2 x i32]
%3 = bitcast [2 x i32]* %2 to i8*
%4 = tail call i32 (i32*, ...) bitcast (i32 (...)* @heir2 to i32 (i32*, ...)*)(i32* %0)
%5 = tail call i32 (i8*, ...) bitcast (i32 (...)* @match to i32 (i8*, ...)*)(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str, i64 0, i64 0))
%6 = icmp eq i32 %5, 0
br i1 %6, label %25, label %7
7: ; preds = %1
%8 = icmp eq i32 %4, 0
br i1 %8, label %9, label %11
9: ; preds = %7
%10 = tail call i32 (...) @needlval()
br label %25
11: ; preds = %7
%12 = getelementptr inbounds i32, i32* %0, i64 1
%13 = load i32, i32* %12
%14 = icmp eq i32 %13, 0
br i1 %14, label %17, label %15
15: ; preds = %11
%16 = tail call i32 (...) @mnem_push()
br label %17
17: ; preds = %15, %11
%18 = getelementptr inbounds [2 x i32], [2 x i32]* %2, i64 0, i64 0
%19 = call i32 @heir1(i32* %18)
%20 = icmp eq i32 %19, 0
br i1 %20, label %23, label %21
21: ; preds = %17
%22 = call i32 (i32*, ...) bitcast (i32 (...)* @rvalue to i32 (i32*, ...)*)(i32* %18)
br label %23
23: ; preds = %21, %17
%24 = call i32 (i32*, ...) bitcast (i32 (...)* @store to i32 (i32*, ...)*)(i32* %0)
br label %25
25: ; preds = %1, %23, %9
%26 = phi i32 [ 0, %9 ], [ 0, %23 ], [ %4, %1 ]
ret i32 %26
}