comptime if does not work as expected

[kbkpbot]

Describe the bug

It seems cgen has some bug when generate code for some comptime $if.

Reproduction Steps

some code extract from vlib/v/tests/comptime/comptime_if_expr_test.v

version.v

const version = 123
const disable_opt_features = true

// Note: the `unknown_fn()` calls are here on purpose, to make sure that anything
// that doesn't match a compile-time condition is not even parsed.
fn ct_expressions() {
        foo := version
        bar := foo
        $if bar == 123 {
                println('bar == 123')
                assert true
        }
        $if bar != 123 {
                unknown_fn()
        } $else $if bar != 124 {
                println('bar != 124')
                assert true
        } $else {
                unknown_fn()
        }
}

fn main() {
        ct_expressions()
}

v run version.v

Expected Behavior

output

bar == 123
bar != 124

Current Behavior

output

bar == 123

Possible Solution

No response

Additional Information/Context

No response

V version

V 0.4.11 460b48a.4f8a3da

Environment details (OS name and version, etc.)

V full version	V 0.4.11 460b48a.4f8a3da
OS	linux, Ubuntu 24.04.3 LTS
Processor	8 cpus, 64bit, little endian, Intel(R) Core(TM) i7-9700 CPU @ 3.00GHz
Memory	3.38GB/15.51GB
V executable	/media/HD/github/kbkpbot/v/v
V last modified time	2025-08-17 01:46:38
V home dir	OK, value: /media/HD/github/kbkpbot/v
VMODULES	OK, value: /home/mars/.vmodules
VTMP	OK, value: /tmp/v_1000
Current working dir	OK, value: /home/mars/v/bug/comptime
Git version	git version 2.43.0
V git status	weekly.2025.17-589-g206fdf4a
.git/config present	true
cc version	cc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
gcc version	gcc (Ubuntu 13.3.0-6ubuntu2~24.04) 13.3.0
clang version	Ubuntu clang version 18.1.3 (1ubuntu1)
tcc version	tcc version 0.9.28rc 2025-02-13 HEAD@f8bd136d (x86_64 Linux)
tcc git status	thirdparty-linux-amd64 696c1d84
emcc version	N/A
glibc version	ldd (Ubuntu GLIBC 2.39-0ubuntu8.5) 2.39

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