Liveness analysis failure

[xtexx]

Zig Version

cffa98e (std.fmt.parseFloat: fix hex-float negative inf, 2025-06-08)

Steps to Reproduce and Observed Behavior

Build the repro:

const S = union {
    a: struct { u12 },
    inline fn makeA() S {
        return .{ .a = .{12} };
    }
};

export fn repro() void {
    for (0..3) |_| _ = S.makeA();
}

Then the compiler crashes at liveness analysis.

The un-reduced code is at xtexx@f6e7e08 (bisection confirmed it is the first bad commit).

Expected Behavior

It should compile.