[nix-shell:~/dev/zig/build]$ ./zig-out/bin/zig astgen a.zig >a.zir

[nix-shell:~/dev/zig/build]$ ./zig-out/bin/zig astgen b.zig >b.zir

[nix-shell:~/dev/zig/build]$ ./zig-out/bin/zig changelist a.zig b.zig
Instruction mappings:
 %14 => %14
 %24 => %22
 %16 => %16
 %22 => %20
 %47 => %45
 %49 => %47
 %30 => %28
 %12 => %12
Extra mappings:
 161 => 153
 33 => 33
 154 => 146
 65 => 57

[nix-shell:~/dev/zig/build]$ cat a.zig
pub fn main() void {
    print();
    const S = if (cond) struct {
        x: i32,

        fn method() void {
            const E = enum { one };
        }
    } else struct {
        x: f32,

        fn ok() void {
            const E2 = enum { two };
        }
    };
}

fn print() void {
    asm volatile ("syscall"
        :
        : [number] "{rax}" (1),
          [arg1] "{rdi}" (1),
          [arg2] "{rsi}" (@ptrToInt("Hello, World!\n")),
          [arg3] "{rdx}" (14)
        : "rcx", "r11", "memory"
    );
    return;
}

[nix-shell:~/dev/zig/build]$ cat b.zig
pub fn main() void {
    print();
    const S = if (cond) struct {
        x: i32,

        fn method() void {
            const E = enum { one };
        }
    } else struct {
        x: f32,

        fn ok() void {}
    };
}

fn print() void {
    asm volatile ("syscall"
        :
        : [number] "{rax}" (1),
          [arg1] "{rdi}" (1),
          [arg2] "{rsi}" (@ptrToInt("Hello, World!\n")),
          [arg3] "{rdx}" (14)
        : "rcx", "r11", "memory"
    );
    return;
}

[nix-shell:~/dev/zig/build]$ cat a.zir
# Source bytes:       533B
# Tokens:             123 (639B)
# AST Nodes:          46 (718B)
# Total ZIR bytes:    1.2841796875KiB
# Instructions:       50 (450B)
# String Table Bytes: 129B
# Extra Data Items:   168 (672B)
%49 = struct_decl({
  [154] pub main line(0) hash(074c0e2d47c9d36545594c7bddf23b38): %0 = block_inline({
    %30 = func([], @Ref.void_type, {
      %1 = dbg_stmt(1, 4)
      %2 = decl_val("print") token_offset:2:5
      %3 = call_chkused(%2, []) node_offset:2:10
      %4 = dbg_stmt(2, 4)
      %9 = block({
        %6 = decl_val("cond") token_offset:3:19
        %7 = as_node(@Ref.bool_type, %6) node_offset:3:19
        %8 = condbr(%7, {
          %16 = struct_decl({
            [33] method line(5) hash(2ca564c250c315ee1fdc364e987fee3f): %10 = block_inline({
              %14 = func([], @Ref.void_type, {
                %11 = dbg_stmt(1, 12)
                %12 = enum_decl({}, {}, {
                  one,
                }) node_offset:7:23
                %13 = ret_coerce(@Ref.void_value) token_offset:8:9
              }) (lbrace=0:17,rbrace=2:8) node_offset:6:9
              %15 = break_inline(%10, %14)
            }) node_offset:6:9
          }, {}, {
            x: @Ref.i32_type,
          }) node_offset:3:25
          %17 = store_to_block_ptr(%5, %16)
          %26 = break(%9, %16)
        }, {
          %24 = struct_decl({
            [65] ok line(11) hash(c90e92151d26cd1991636515a27b1796): %18 = block_inline({
              %22 = func([], @Ref.void_type, {
                %19 = dbg_stmt(1, 12)
                %20 = enum_decl({}, {}, {
                  two,
                }) node_offset:13:24
                %21 = ret_coerce(@Ref.void_value) token_offset:14:9
              }) (lbrace=0:13,rbrace=2:8) node_offset:12:9
              %23 = break_inline(%18, %22)
            }) node_offset:12:9
          }, {}, {
            x: @Ref.f32_type,
          }) node_offset:9:12
          %25 = store_to_block_ptr(%5, %24)
          %27 = break(%9, %24)
        }) node_offset:3:15
      }) node_offset:3:15
      %29 = ret_coerce(@Ref.void_value) token_offset:16:1
    }) (lbrace=0:19,rbrace=15:0) node_offset:1:5
    %31 = break_inline(%0, %30)
  }) node_offset:1:5
  [161] print line(17) hash(769c011edaf1727ed53de30cb52508c3): %32 = block_inline({
    %47 = func([], @Ref.void_type, {
      %33 = dbg_stmt(1, 4)
      %34 = str("syscall")
      %35 = as_node(@Ref.const_slice_u8_type, %34) node_offset:19:19
      %36 = as_node(@Ref.usize_type, @Ref.one) node_offset:21:29
      %37 = as_node(@Ref.usize_type, @Ref.one) node_offset:22:27
      %38 = str("Hello, World!\n")
      %39 = ptr_to_int(%38) node_offset:23:27
      %40 = as_node(@Ref.usize_type, %39) node_offset:23:27
      %41 = int(14)
      %42 = as_node(@Ref.usize_type, %41) node_offset:24:27
      %43 = extended(asm(volatile, %35, input(number, "{rax}", %36), input(arg1, "{rdi}", %37), input(arg2, "{rsi}", %40), input(arg3, "{rdx}", %42)rcx, r11, memory)) node_offset:19:5
      %44 = ensure_result_used(%43) node_offset:19:5
      %45 = dbg_stmt(9, 4)
      %46 = ret_node(@Ref.void_value) node_offset:27:5
    }) (lbrace=0:16,rbrace=10:0) node_offset:18:1
    %48 = break_inline(%32, %47)
  }) node_offset:18:1
}, {}, {}) node_offset:1:1

[nix-shell:~/dev/zig/build]$ cat b.zir
# Source bytes:       487B
# Tokens:             115 (599B)
# AST Nodes:          43 (679B)
# Total ZIR bytes:    1.228515625KiB
# Instructions:       48 (432B)
# String Table Bytes: 122B
# Extra Data Items:   160 (640B)
%47 = struct_decl({
  [146] pub main line(0) hash(d560f9b12c8f5afc0e244fe126be28d7): %0 = block_inline({
    %28 = func([], @Ref.void_type, {
      %1 = dbg_stmt(1, 4)
      %2 = decl_val("print") token_offset:2:5
      %3 = call_chkused(%2, []) node_offset:2:10
      %4 = dbg_stmt(2, 4)
      %9 = block({
        %6 = decl_val("cond") token_offset:3:19
        %7 = as_node(@Ref.bool_type, %6) node_offset:3:19
        %8 = condbr(%7, {
          %16 = struct_decl({
            [33] method line(5) hash(2ca564c250c315ee1fdc364e987fee3f): %10 = block_inline({
              %14 = func([], @Ref.void_type, {
                %11 = dbg_stmt(1, 12)
                %12 = enum_decl({}, {}, {
                  one,
                }) node_offset:7:23
                %13 = ret_coerce(@Ref.void_value) token_offset:8:9
              }) (lbrace=0:17,rbrace=2:8) node_offset:6:9
              %15 = break_inline(%10, %14)
            }) node_offset:6:9
          }, {}, {
            x: @Ref.i32_type,
          }) node_offset:3:25
          %17 = store_to_block_ptr(%5, %16)
          %24 = break(%9, %16)
        }, {
          %22 = struct_decl({
            [57] ok line(11) hash(64638a6529d0e99e7dad955d26d3ec0d): %18 = block_inline({
              %20 = func([], @Ref.void_type, {
                %19 = ret_coerce(@Ref.void_value) token_offset:12:23
              }) (lbrace=0:13,rbrace=0:1) node_offset:12:9
              %21 = break_inline(%18, %20)
            }) node_offset:12:9
          }, {}, {
            x: @Ref.f32_type,
          }) node_offset:9:12
          %23 = store_to_block_ptr(%5, %22)
          %25 = break(%9, %22)
        }) node_offset:3:15
      }) node_offset:3:15
      %27 = ret_coerce(@Ref.void_value) token_offset:14:1
    }) (lbrace=0:19,rbrace=13:0) node_offset:1:5
    %29 = break_inline(%0, %28)
  }) node_offset:1:5
  [153] print line(15) hash(769c011edaf1727ed53de30cb52508c3): %30 = block_inline({
    %45 = func([], @Ref.void_type, {
      %31 = dbg_stmt(1, 4)
      %32 = str("syscall")
      %33 = as_node(@Ref.const_slice_u8_type, %32) node_offset:17:19
      %34 = as_node(@Ref.usize_type, @Ref.one) node_offset:19:29
      %35 = as_node(@Ref.usize_type, @Ref.one) node_offset:20:27
      %36 = str("Hello, World!\n")
      %37 = ptr_to_int(%36) node_offset:21:27
      %38 = as_node(@Ref.usize_type, %37) node_offset:21:27
      %39 = int(14)
      %40 = as_node(@Ref.usize_type, %39) node_offset:22:27
      %41 = extended(asm(volatile, %33, input(number, "{rax}", %34), input(arg1, "{rdi}", %35), input(arg2, "{rsi}", %38), input(arg3, "{rdx}", %40)rcx, r11, memory)) node_offset:17:5
      %42 = ensure_result_used(%41) node_offset:17:5
      %43 = dbg_stmt(9, 4)
      %44 = ret_node(@Ref.void_value) node_offset:25:5
    }) (lbrace=0:16,rbrace=10:0) node_offset:16:1
    %46 = break_inline(%30, %45)
  }) node_offset:16:1
}, {}, {}) node_offset:1:1